Removed openssl, and curl, and added mbedded tls.curl-removal

Almost fully removed curl, needs more testing.

Fixed most issues, now trying to cross compile.

Fix?

Sigh.

1 files changed, 5395 insertions, 0 deletions

diff --git a/lib/mbedtls-2.27.0/library/psa_crypto.c b/lib/mbedtls-2.27.0/library/psa_crypto.c
new file mode 100644
index 0000000..a424c89
--- /dev/null
+++ b/lib/mbedtls-2.27.0/library/psa_crypto.c
@@ -0,0 +1,5395 @@
+/*
+ *  PSA crypto layer on top of Mbed TLS crypto
+ */
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include "common.h"
+
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+
+#if defined(MBEDTLS_PSA_CRYPTO_CONFIG)
+#include "check_crypto_config.h"
+#endif
+
+#include "psa/crypto.h"
+
+#include "psa_crypto_cipher.h"
+#include "psa_crypto_core.h"
+#include "psa_crypto_invasive.h"
+#include "psa_crypto_driver_wrappers.h"
+#include "psa_crypto_ecp.h"
+#include "psa_crypto_hash.h"
+#include "psa_crypto_mac.h"
+#include "psa_crypto_rsa.h"
+#include "psa_crypto_ecp.h"
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+#include "psa_crypto_se.h"
+#endif
+#include "psa_crypto_slot_management.h"
+/* Include internal declarations that are useful for implementing persistently
+ * stored keys. */
+#include "psa_crypto_storage.h"
+
+#include "psa_crypto_random_impl.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include "mbedtls/platform.h"
+#if !defined(MBEDTLS_PLATFORM_C)
+#define mbedtls_calloc calloc
+#define mbedtls_free   free
+#endif
+
+#include "mbedtls/aes.h"
+#include "mbedtls/arc4.h"
+#include "mbedtls/asn1.h"
+#include "mbedtls/asn1write.h"
+#include "mbedtls/bignum.h"
+#include "mbedtls/blowfish.h"
+#include "mbedtls/camellia.h"
+#include "mbedtls/chacha20.h"
+#include "mbedtls/chachapoly.h"
+#include "mbedtls/cipher.h"
+#include "mbedtls/ccm.h"
+#include "mbedtls/cmac.h"
+#include "mbedtls/des.h"
+#include "mbedtls/ecdh.h"
+#include "mbedtls/ecp.h"
+#include "mbedtls/entropy.h"
+#include "mbedtls/error.h"
+#include "mbedtls/gcm.h"
+#include "mbedtls/md2.h"
+#include "mbedtls/md4.h"
+#include "mbedtls/md5.h"
+#include "mbedtls/md.h"
+#include "mbedtls/md_internal.h"
+#include "mbedtls/pk.h"
+#include "mbedtls/pk_internal.h"
+#include "mbedtls/platform_util.h"
+#include "mbedtls/error.h"
+#include "mbedtls/ripemd160.h"
+#include "mbedtls/rsa.h"
+#include "mbedtls/sha1.h"
+#include "mbedtls/sha256.h"
+#include "mbedtls/sha512.h"
+#include "mbedtls/xtea.h"
+
+#define ARRAY_LENGTH( array ) ( sizeof( array ) / sizeof( *( array ) ) )
+
+/****************************************************************/
+/* Global data, support functions and library management */
+/****************************************************************/
+
+static int key_type_is_raw_bytes( psa_key_type_t type )
+{
+    return( PSA_KEY_TYPE_IS_UNSTRUCTURED( type ) );
+}
+
+/* Values for psa_global_data_t::rng_state */
+#define RNG_NOT_INITIALIZED 0
+#define RNG_INITIALIZED 1
+#define RNG_SEEDED 2
+
+typedef struct
+{
+    mbedtls_psa_random_context_t rng;
+    unsigned initialized : 1;
+    unsigned rng_state : 2;
+} psa_global_data_t;
+
+static psa_global_data_t global_data;
+
+#if !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+mbedtls_psa_drbg_context_t *const mbedtls_psa_random_state =
+    &global_data.rng.drbg;
+#endif
+
+#define GUARD_MODULE_INITIALIZED        \
+    if( global_data.initialized == 0 )  \
+        return( PSA_ERROR_BAD_STATE );
+
+psa_status_t mbedtls_to_psa_error( int ret )
+{
+    /* Mbed TLS error codes can combine a high-level error code and a
+     * low-level error code. The low-level error usually reflects the
+     * root cause better, so dispatch on that preferably. */
+    int low_level_ret = - ( -ret & 0x007f );
+    switch( low_level_ret != 0 ? low_level_ret : ret )
+    {
+        case 0:
+            return( PSA_SUCCESS );
+
+        case MBEDTLS_ERR_AES_INVALID_KEY_LENGTH:
+        case MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH:
+        case MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_AES_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_ARC4_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_ASN1_OUT_OF_DATA:
+        case MBEDTLS_ERR_ASN1_UNEXPECTED_TAG:
+        case MBEDTLS_ERR_ASN1_INVALID_LENGTH:
+        case MBEDTLS_ERR_ASN1_LENGTH_MISMATCH:
+        case MBEDTLS_ERR_ASN1_INVALID_DATA:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_ASN1_ALLOC_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+        case MBEDTLS_ERR_ASN1_BUF_TOO_SMALL:
+            return( PSA_ERROR_BUFFER_TOO_SMALL );
+
+#if defined(MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA)
+        case MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA:
+#elif defined(MBEDTLS_ERR_BLOWFISH_INVALID_KEY_LENGTH)
+        case MBEDTLS_ERR_BLOWFISH_INVALID_KEY_LENGTH:
+#endif
+        case MBEDTLS_ERR_BLOWFISH_INVALID_INPUT_LENGTH:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_BLOWFISH_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+#if defined(MBEDTLS_ERR_CAMELLIA_BAD_INPUT_DATA)
+        case MBEDTLS_ERR_CAMELLIA_BAD_INPUT_DATA:
+#elif defined(MBEDTLS_ERR_CAMELLIA_INVALID_KEY_LENGTH)
+        case MBEDTLS_ERR_CAMELLIA_INVALID_KEY_LENGTH:
+#endif
+        case MBEDTLS_ERR_CAMELLIA_INVALID_INPUT_LENGTH:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_CAMELLIA_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_CCM_BAD_INPUT:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_CCM_AUTH_FAILED:
+            return( PSA_ERROR_INVALID_SIGNATURE );
+        case MBEDTLS_ERR_CCM_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+
+        case MBEDTLS_ERR_CHACHAPOLY_BAD_STATE:
+            return( PSA_ERROR_BAD_STATE );
+        case MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED:
+            return( PSA_ERROR_INVALID_SIGNATURE );
+
+        case MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_CIPHER_ALLOC_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+        case MBEDTLS_ERR_CIPHER_INVALID_PADDING:
+            return( PSA_ERROR_INVALID_PADDING );
+        case MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_CIPHER_AUTH_FAILED:
+            return( PSA_ERROR_INVALID_SIGNATURE );
+        case MBEDTLS_ERR_CIPHER_INVALID_CONTEXT:
+            return( PSA_ERROR_CORRUPTION_DETECTED );
+        case MBEDTLS_ERR_CIPHER_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_CMAC_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+#if !( defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) ||      \
+       defined(MBEDTLS_PSA_HMAC_DRBG_MD_TYPE) )
+        /* Only check CTR_DRBG error codes if underlying mbedtls_xxx
+         * functions are passed a CTR_DRBG instance. */
+        case MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_ENTROPY );
+        case MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG:
+        case MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR:
+            return( PSA_ERROR_INSUFFICIENT_ENTROPY );
+#endif
+
+        case MBEDTLS_ERR_DES_INVALID_INPUT_LENGTH:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_DES_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED:
+        case MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE:
+        case MBEDTLS_ERR_ENTROPY_SOURCE_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_ENTROPY );
+
+        case MBEDTLS_ERR_GCM_AUTH_FAILED:
+            return( PSA_ERROR_INVALID_SIGNATURE );
+        case MBEDTLS_ERR_GCM_BAD_INPUT:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_GCM_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+#if !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) &&        \
+    defined(MBEDTLS_PSA_HMAC_DRBG_MD_TYPE)
+        /* Only check HMAC_DRBG error codes if underlying mbedtls_xxx
+         * functions are passed a HMAC_DRBG instance. */
+        case MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_ENTROPY );
+        case MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG:
+        case MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR:
+            return( PSA_ERROR_INSUFFICIENT_ENTROPY );
+#endif
+
+        case MBEDTLS_ERR_MD2_HW_ACCEL_FAILED:
+        case MBEDTLS_ERR_MD4_HW_ACCEL_FAILED:
+        case MBEDTLS_ERR_MD5_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_MD_BAD_INPUT_DATA:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_MD_ALLOC_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+        case MBEDTLS_ERR_MD_FILE_IO_ERROR:
+            return( PSA_ERROR_STORAGE_FAILURE );
+        case MBEDTLS_ERR_MD_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_MPI_FILE_IO_ERROR:
+            return( PSA_ERROR_STORAGE_FAILURE );
+        case MBEDTLS_ERR_MPI_BAD_INPUT_DATA:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_MPI_INVALID_CHARACTER:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL:
+            return( PSA_ERROR_BUFFER_TOO_SMALL );
+        case MBEDTLS_ERR_MPI_NEGATIVE_VALUE:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_MPI_DIVISION_BY_ZERO:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_MPI_NOT_ACCEPTABLE:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_MPI_ALLOC_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+
+        case MBEDTLS_ERR_PK_ALLOC_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+        case MBEDTLS_ERR_PK_TYPE_MISMATCH:
+        case MBEDTLS_ERR_PK_BAD_INPUT_DATA:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_PK_FILE_IO_ERROR:
+            return( PSA_ERROR_STORAGE_FAILURE );
+        case MBEDTLS_ERR_PK_KEY_INVALID_VERSION:
+        case MBEDTLS_ERR_PK_KEY_INVALID_FORMAT:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_PK_UNKNOWN_PK_ALG:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_PK_PASSWORD_REQUIRED:
+        case MBEDTLS_ERR_PK_PASSWORD_MISMATCH:
+            return( PSA_ERROR_NOT_PERMITTED );
+        case MBEDTLS_ERR_PK_INVALID_PUBKEY:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_PK_INVALID_ALG:
+        case MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE:
+        case MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_PK_SIG_LEN_MISMATCH:
+            return( PSA_ERROR_INVALID_SIGNATURE );
+        case MBEDTLS_ERR_PK_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+        case MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED:
+            return( PSA_ERROR_NOT_SUPPORTED );
+
+        case MBEDTLS_ERR_RIPEMD160_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_RSA_BAD_INPUT_DATA:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_RSA_INVALID_PADDING:
+            return( PSA_ERROR_INVALID_PADDING );
+        case MBEDTLS_ERR_RSA_KEY_GEN_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+        case MBEDTLS_ERR_RSA_KEY_CHECK_FAILED:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_RSA_PUBLIC_FAILED:
+        case MBEDTLS_ERR_RSA_PRIVATE_FAILED:
+            return( PSA_ERROR_CORRUPTION_DETECTED );
+        case MBEDTLS_ERR_RSA_VERIFY_FAILED:
+            return( PSA_ERROR_INVALID_SIGNATURE );
+        case MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE:
+            return( PSA_ERROR_BUFFER_TOO_SMALL );
+        case MBEDTLS_ERR_RSA_RNG_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_ENTROPY );
+        case MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_RSA_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_SHA1_HW_ACCEL_FAILED:
+        case MBEDTLS_ERR_SHA256_HW_ACCEL_FAILED:
+        case MBEDTLS_ERR_SHA512_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_XTEA_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_ECP_BAD_INPUT_DATA:
+        case MBEDTLS_ERR_ECP_INVALID_KEY:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        case MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL:
+            return( PSA_ERROR_BUFFER_TOO_SMALL );
+        case MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE:
+            return( PSA_ERROR_NOT_SUPPORTED );
+        case MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH:
+        case MBEDTLS_ERR_ECP_VERIFY_FAILED:
+            return( PSA_ERROR_INVALID_SIGNATURE );
+        case MBEDTLS_ERR_ECP_ALLOC_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+        case MBEDTLS_ERR_ECP_RANDOM_FAILED:
+            return( PSA_ERROR_INSUFFICIENT_ENTROPY );
+        case MBEDTLS_ERR_ECP_HW_ACCEL_FAILED:
+            return( PSA_ERROR_HARDWARE_FAILURE );
+
+        case MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED:
+            return( PSA_ERROR_CORRUPTION_DETECTED );
+
+        default:
+            return( PSA_ERROR_GENERIC_ERROR );
+    }
+}
+
+
+
+
+/****************************************************************/
+/* Key management */
+/****************************************************************/
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+static inline int psa_key_slot_is_external( const psa_key_slot_t *slot )
+{
+    return( psa_key_lifetime_is_external( slot->attr.lifetime ) );
+}
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+/* For now the MBEDTLS_PSA_ACCEL_ guards are also used here since the
+ * current test driver in key_management.c is using this function
+ * when accelerators are used for ECC key pair and public key.
+ * Once that dependency is resolved these guards can be removed.
+ */
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) || \
+    defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY)
+mbedtls_ecp_group_id mbedtls_ecc_group_of_psa( psa_ecc_family_t curve,
+                                               size_t bits,
+                                               int bits_is_sloppy )
+{
+    switch( curve )
+    {
+        case PSA_ECC_FAMILY_SECP_R1:
+            switch( bits )
+            {
+#if defined(PSA_WANT_ECC_SECP_R1_192)
+                case 192:
+                    return( MBEDTLS_ECP_DP_SECP192R1 );
+#endif
+#if defined(PSA_WANT_ECC_SECP_R1_224)
+                case 224:
+                    return( MBEDTLS_ECP_DP_SECP224R1 );
+#endif
+#if defined(PSA_WANT_ECC_SECP_R1_256)
+                case 256:
+                    return( MBEDTLS_ECP_DP_SECP256R1 );
+#endif
+#if defined(PSA_WANT_ECC_SECP_R1_384)
+                case 384:
+                    return( MBEDTLS_ECP_DP_SECP384R1 );
+#endif
+#if defined(PSA_WANT_ECC_SECP_R1_521)
+                case 521:
+                    return( MBEDTLS_ECP_DP_SECP521R1 );
+                case 528:
+                    if( bits_is_sloppy )
+                        return( MBEDTLS_ECP_DP_SECP521R1 );
+                    break;
+#endif
+            }
+            break;
+
+        case PSA_ECC_FAMILY_BRAINPOOL_P_R1:
+            switch( bits )
+            {
+#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_256)
+                case 256:
+                    return( MBEDTLS_ECP_DP_BP256R1 );
+#endif
+#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_384)
+                case 384:
+                    return( MBEDTLS_ECP_DP_BP384R1 );
+#endif
+#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_512)
+                case 512:
+                    return( MBEDTLS_ECP_DP_BP512R1 );
+#endif
+            }
+            break;
+
+        case PSA_ECC_FAMILY_MONTGOMERY:
+            switch( bits )
+            {
+#if defined(PSA_WANT_ECC_MONTGOMERY_255)
+                case 255:
+                    return( MBEDTLS_ECP_DP_CURVE25519 );
+                case 256:
+                    if( bits_is_sloppy )
+                        return( MBEDTLS_ECP_DP_CURVE25519 );
+                    break;
+#endif
+#if defined(PSA_WANT_ECC_MONTGOMERY_448)
+                case 448:
+                    return( MBEDTLS_ECP_DP_CURVE448 );
+#endif
+            }
+            break;
+
+        case PSA_ECC_FAMILY_SECP_K1:
+            switch( bits )
+            {
+#if defined(PSA_WANT_ECC_SECP_K1_192)
+                case 192:
+                    return( MBEDTLS_ECP_DP_SECP192K1 );
+#endif
+#if defined(PSA_WANT_ECC_SECP_K1_224)
+                case 224:
+                    return( MBEDTLS_ECP_DP_SECP224K1 );
+#endif
+#if defined(PSA_WANT_ECC_SECP_K1_256)
+                case 256:
+                    return( MBEDTLS_ECP_DP_SECP256K1 );
+#endif
+            }
+            break;
+    }
+
+    (void) bits_is_sloppy;
+    return( MBEDTLS_ECP_DP_NONE );
+}
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) ||
+        * defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY) */
+
+static psa_status_t validate_unstructured_key_bit_size( psa_key_type_t type,
+                                                        size_t bits )
+{
+    /* Check that the bit size is acceptable for the key type */
+    switch( type )
+    {
+        case PSA_KEY_TYPE_RAW_DATA:
+        case PSA_KEY_TYPE_HMAC:
+        case PSA_KEY_TYPE_DERIVE:
+            break;
+#if defined(PSA_WANT_KEY_TYPE_AES)
+        case PSA_KEY_TYPE_AES:
+            if( bits != 128 && bits != 192 && bits != 256 )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+            break;
+#endif
+#if defined(PSA_WANT_KEY_TYPE_CAMELLIA)
+        case PSA_KEY_TYPE_CAMELLIA:
+            if( bits != 128 && bits != 192 && bits != 256 )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+            break;
+#endif
+#if defined(PSA_WANT_KEY_TYPE_DES)
+        case PSA_KEY_TYPE_DES:
+            if( bits != 64 && bits != 128 && bits != 192 )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+            break;
+#endif
+#if defined(PSA_WANT_KEY_TYPE_ARC4)
+        case PSA_KEY_TYPE_ARC4:
+            if( bits < 8 || bits > 2048 )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+            break;
+#endif
+#if defined(PSA_WANT_KEY_TYPE_CHACHA20)
+        case PSA_KEY_TYPE_CHACHA20:
+            if( bits != 256 )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+            break;
+#endif
+        default:
+            return( PSA_ERROR_NOT_SUPPORTED );
+    }
+    if( bits % 8 != 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    return( PSA_SUCCESS );
+}
+
+/** Check whether a given key type is valid for use with a given MAC algorithm
+ *
+ * Upon successful return of this function, the behavior of #PSA_MAC_LENGTH
+ * when called with the validated \p algorithm and \p key_type is well-defined.
+ *
+ * \param[in] algorithm     The specific MAC algorithm (can be wildcard).
+ * \param[in] key_type      The key type of the key to be used with the
+ *                          \p algorithm.
+ *
+ * \retval #PSA_SUCCESS
+ *         The \p key_type is valid for use with the \p algorithm
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ *         The \p key_type is not valid for use with the \p algorithm
+ */
+MBEDTLS_STATIC_TESTABLE psa_status_t psa_mac_key_can_do(
+    psa_algorithm_t algorithm,
+    psa_key_type_t key_type )
+{
+    if( PSA_ALG_IS_HMAC( algorithm ) )
+    {
+        if( key_type == PSA_KEY_TYPE_HMAC )
+            return( PSA_SUCCESS );
+    }
+
+    if( PSA_ALG_IS_BLOCK_CIPHER_MAC( algorithm ) )
+    {
+        /* Check that we're calling PSA_BLOCK_CIPHER_BLOCK_LENGTH with a cipher
+         * key. */
+        if( ( key_type & PSA_KEY_TYPE_CATEGORY_MASK ) ==
+            PSA_KEY_TYPE_CATEGORY_SYMMETRIC )
+        {
+            /* PSA_BLOCK_CIPHER_BLOCK_LENGTH returns 1 for stream ciphers and
+             * the block length (larger than 1) for block ciphers. */
+            if( PSA_BLOCK_CIPHER_BLOCK_LENGTH( key_type ) > 1 )
+                return( PSA_SUCCESS );
+        }
+    }
+
+    return( PSA_ERROR_INVALID_ARGUMENT );
+}
+
+psa_status_t psa_allocate_buffer_to_slot( psa_key_slot_t *slot,
+                                          size_t buffer_length )
+{
+    if( slot->key.data != NULL )
+        return( PSA_ERROR_ALREADY_EXISTS );
+
+    slot->key.data = mbedtls_calloc( 1, buffer_length );
+    if( slot->key.data == NULL )
+        return( PSA_ERROR_INSUFFICIENT_MEMORY );
+
+    slot->key.bytes = buffer_length;
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_copy_key_material_into_slot( psa_key_slot_t *slot,
+                                              const uint8_t* data,
+                                              size_t data_length )
+{
+    psa_status_t status = psa_allocate_buffer_to_slot( slot,
+                                                       data_length );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    memcpy( slot->key.data, data, data_length );
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_import_key_into_slot(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *data, size_t data_length,
+    uint8_t *key_buffer, size_t key_buffer_size,
+    size_t *key_buffer_length, size_t *bits )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_type_t type = attributes->core.type;
+
+    /* zero-length keys are never supported. */
+    if( data_length == 0 )
+        return( PSA_ERROR_NOT_SUPPORTED );
+
+    if( key_type_is_raw_bytes( type ) )
+    {
+        *bits = PSA_BYTES_TO_BITS( data_length );
+
+        /* Ensure that the bytes-to-bits conversion hasn't overflown. */
+        if( data_length > SIZE_MAX / 8 )
+            return( PSA_ERROR_NOT_SUPPORTED );
+
+        /* Enforce a size limit, and in particular ensure that the bit
+         * size fits in its representation type. */
+        if( ( *bits ) > PSA_MAX_KEY_BITS )
+            return( PSA_ERROR_NOT_SUPPORTED );
+
+        status = validate_unstructured_key_bit_size( type, *bits );
+        if( status != PSA_SUCCESS )
+            return( status );
+
+        /* Copy the key material. */
+        memcpy( key_buffer, data, data_length );
+        *key_buffer_length = data_length;
+        (void)key_buffer_size;
+
+        return( PSA_SUCCESS );
+    }
+    else if( PSA_KEY_TYPE_IS_ASYMMETRIC( type ) )
+    {
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY)
+        if( PSA_KEY_TYPE_IS_ECC( type ) )
+        {
+            return( mbedtls_psa_ecp_import_key( attributes,
+                                                data, data_length,
+                                                key_buffer, key_buffer_size,
+                                                key_buffer_length,
+                                                bits ) );
+        }
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) */
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY)
+        if( PSA_KEY_TYPE_IS_RSA( type ) )
+        {
+            return( mbedtls_psa_rsa_import_key( attributes,
+                                                data, data_length,
+                                                key_buffer, key_buffer_size,
+                                                key_buffer_length,
+                                                bits ) );
+        }
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */
+    }
+
+    return( PSA_ERROR_NOT_SUPPORTED );
+}
+
+/** Calculate the intersection of two algorithm usage policies.
+ *
+ * Return 0 (which allows no operation) on incompatibility.
+ */
+static psa_algorithm_t psa_key_policy_algorithm_intersection(
+    psa_key_type_t key_type,
+    psa_algorithm_t alg1,
+    psa_algorithm_t alg2 )
+{
+    /* Common case: both sides actually specify the same policy. */
+    if( alg1 == alg2 )
+        return( alg1 );
+    /* If the policies are from the same hash-and-sign family, check
+     * if one is a wildcard. If so the other has the specific algorithm. */
+    if( PSA_ALG_IS_HASH_AND_SIGN( alg1 ) &&
+        PSA_ALG_IS_HASH_AND_SIGN( alg2 ) &&
+        ( alg1 & ~PSA_ALG_HASH_MASK ) == ( alg2 & ~PSA_ALG_HASH_MASK ) )
+    {
+        if( PSA_ALG_SIGN_GET_HASH( alg1 ) == PSA_ALG_ANY_HASH )
+            return( alg2 );
+        if( PSA_ALG_SIGN_GET_HASH( alg2 ) == PSA_ALG_ANY_HASH )
+            return( alg1 );
+    }
+    /* If the policies are from the same AEAD family, check whether
+     * one of them is a minimum-tag-length wildcard. Calculate the most
+     * restrictive tag length. */
+    if( PSA_ALG_IS_AEAD( alg1 ) && PSA_ALG_IS_AEAD( alg2 ) &&
+        ( PSA_ALG_AEAD_WITH_SHORTENED_TAG( alg1, 0 ) ==
+          PSA_ALG_AEAD_WITH_SHORTENED_TAG( alg2, 0 ) ) )
+    {
+        size_t alg1_len = PSA_ALG_AEAD_GET_TAG_LENGTH( alg1 );
+        size_t alg2_len = PSA_ALG_AEAD_GET_TAG_LENGTH( alg2 );
+        size_t restricted_len = alg1_len > alg2_len ? alg1_len : alg2_len;
+
+        /* If both are wildcards, return most restrictive wildcard */
+        if( ( ( alg1 & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) &&
+            ( ( alg2 & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) )
+        {
+            return( PSA_ALG_AEAD_WITH_AT_LEAST_THIS_LENGTH_TAG(
+                        alg1, restricted_len ) );
+        }
+        /* If only one is a wildcard, return specific algorithm if compatible. */
+        if( ( ( alg1 & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) &&
+            ( alg1_len <= alg2_len ) )
+        {
+            return( alg2 );
+        }
+        if( ( ( alg2 & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) &&
+            ( alg2_len <= alg1_len ) )
+        {
+            return( alg1 );
+        }
+    }
+    /* If the policies are from the same MAC family, check whether one
+     * of them is a minimum-MAC-length policy. Calculate the most
+     * restrictive tag length. */
+    if( PSA_ALG_IS_MAC( alg1 ) && PSA_ALG_IS_MAC( alg2 ) &&
+        ( PSA_ALG_FULL_LENGTH_MAC( alg1 ) ==
+          PSA_ALG_FULL_LENGTH_MAC( alg2 ) ) )
+    {
+        /* Validate the combination of key type and algorithm. Since the base
+         * algorithm of alg1 and alg2 are the same, we only need this once. */
+        if( PSA_SUCCESS != psa_mac_key_can_do( alg1, key_type ) )
+            return( 0 );
+
+        /* Get the (exact or at-least) output lengths for both sides of the
+         * requested intersection. None of the currently supported algorithms
+         * have an output length dependent on the actual key size, so setting it
+         * to a bogus value of 0 is currently OK.
+         *
+         * Note that for at-least-this-length wildcard algorithms, the output
+         * length is set to the shortest allowed length, which allows us to
+         * calculate the most restrictive tag length for the intersection. */
+        size_t alg1_len = PSA_MAC_LENGTH( key_type, 0, alg1 );
+        size_t alg2_len = PSA_MAC_LENGTH( key_type, 0, alg2 );
+        size_t restricted_len = alg1_len > alg2_len ? alg1_len : alg2_len;
+
+        /* If both are wildcards, return most restrictive wildcard */
+        if( ( ( alg1 & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) &&
+            ( ( alg2 & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) )
+        {
+            return( PSA_ALG_AT_LEAST_THIS_LENGTH_MAC( alg1, restricted_len ) );
+        }
+
+        /* If only one is an at-least-this-length policy, the intersection would
+         * be the other (fixed-length) policy as long as said fixed length is
+         * equal to or larger than the shortest allowed length. */
+        if( ( alg1 & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 )
+        {
+            return( ( alg1_len <= alg2_len ) ? alg2 : 0 );
+        }
+        if( ( alg2 & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 )
+        {
+            return( ( alg2_len <= alg1_len ) ? alg1 : 0 );
+        }
+
+        /* If none of them are wildcards, check whether they define the same tag
+         * length. This is still possible here when one is default-length and
+         * the other specific-length. Ensure to always return the
+         * specific-length version for the intersection. */
+        if( alg1_len == alg2_len )
+            return( PSA_ALG_TRUNCATED_MAC( alg1, alg1_len ) );
+    }
+    /* If the policies are incompatible, allow nothing. */
+    return( 0 );
+}
+
+static int psa_key_algorithm_permits( psa_key_type_t key_type,
+                                      psa_algorithm_t policy_alg,
+                                      psa_algorithm_t requested_alg )
+{
+    /* Common case: the policy only allows requested_alg. */
+    if( requested_alg == policy_alg )
+        return( 1 );
+    /* If policy_alg is a hash-and-sign with a wildcard for the hash,
+     * and requested_alg is the same hash-and-sign family with any hash,
+     * then requested_alg is compliant with policy_alg. */
+    if( PSA_ALG_IS_HASH_AND_SIGN( requested_alg ) &&
+        PSA_ALG_SIGN_GET_HASH( policy_alg ) == PSA_ALG_ANY_HASH )
+    {
+        return( ( policy_alg & ~PSA_ALG_HASH_MASK ) ==
+                ( requested_alg & ~PSA_ALG_HASH_MASK ) );
+    }
+    /* If policy_alg is a wildcard AEAD algorithm of the same base as
+     * the requested algorithm, check the requested tag length to be
+     * equal-length or longer than the wildcard-specified length. */
+    if( PSA_ALG_IS_AEAD( policy_alg ) &&
+        PSA_ALG_IS_AEAD( requested_alg ) &&
+        ( PSA_ALG_AEAD_WITH_SHORTENED_TAG( policy_alg, 0 ) ==
+          PSA_ALG_AEAD_WITH_SHORTENED_TAG( requested_alg, 0 ) ) &&
+        ( ( policy_alg & PSA_ALG_AEAD_AT_LEAST_THIS_LENGTH_FLAG ) != 0 ) )
+    {
+        return( PSA_ALG_AEAD_GET_TAG_LENGTH( policy_alg ) <=
+                PSA_ALG_AEAD_GET_TAG_LENGTH( requested_alg ) );
+    }
+    /* If policy_alg is a MAC algorithm of the same base as the requested
+     * algorithm, check whether their MAC lengths are compatible. */
+    if( PSA_ALG_IS_MAC( policy_alg ) &&
+        PSA_ALG_IS_MAC( requested_alg ) &&
+        ( PSA_ALG_FULL_LENGTH_MAC( policy_alg ) ==
+          PSA_ALG_FULL_LENGTH_MAC( requested_alg ) ) )
+    {
+        /* Validate the combination of key type and algorithm. Since the policy
+         * and requested algorithms are the same, we only need this once. */
+        if( PSA_SUCCESS != psa_mac_key_can_do( policy_alg, key_type ) )
+            return( 0 );
+
+        /* Get both the requested output length for the algorithm which is to be
+         * verified, and the default output length for the base algorithm.
+         * Note that none of the currently supported algorithms have an output
+         * length dependent on actual key size, so setting it to a bogus value
+         * of 0 is currently OK. */
+        size_t requested_output_length = PSA_MAC_LENGTH(
+                                            key_type, 0, requested_alg );
+        size_t default_output_length = PSA_MAC_LENGTH(
+                                        key_type, 0,
+                                        PSA_ALG_FULL_LENGTH_MAC( requested_alg ) );
+
+        /* If the policy is default-length, only allow an algorithm with
+         * a declared exact-length matching the default. */
+        if( PSA_MAC_TRUNCATED_LENGTH( policy_alg ) == 0 )
+            return( requested_output_length == default_output_length );
+
+        /* If the requested algorithm is default-length, allow it if the policy
+         * length exactly matches the default length. */
+        if( PSA_MAC_TRUNCATED_LENGTH( requested_alg ) == 0 &&
+            PSA_MAC_TRUNCATED_LENGTH( policy_alg ) == default_output_length )
+        {
+            return( 1 );
+        }
+
+        /* If policy_alg is an at-least-this-length wildcard MAC algorithm,
+         * check for the requested MAC length to be equal to or longer than the
+         * minimum allowed length. */
+        if( ( policy_alg & PSA_ALG_MAC_AT_LEAST_THIS_LENGTH_FLAG ) != 0 )
+        {
+            return( PSA_MAC_TRUNCATED_LENGTH( policy_alg ) <=
+                    requested_output_length );
+        }
+    }
+    /* If policy_alg is a generic key agreement operation, then using it for
+     * a key derivation with that key agreement should also be allowed. This
+     * behaviour is expected to be defined in a future specification version. */
+    if( PSA_ALG_IS_RAW_KEY_AGREEMENT( policy_alg ) &&
+        PSA_ALG_IS_KEY_AGREEMENT( requested_alg ) )
+    {
+        return( PSA_ALG_KEY_AGREEMENT_GET_BASE( requested_alg ) ==
+                policy_alg );
+    }
+    /* If it isn't explicitly permitted, it's forbidden. */
+    return( 0 );
+}
+
+/** Test whether a policy permits an algorithm.
+ *
+ * The caller must test usage flags separately.
+ *
+ * \note This function requires providing the key type for which the policy is
+ *       being validated, since some algorithm policy definitions (e.g. MAC)
+ *       have different properties depending on what kind of cipher it is
+ *       combined with.
+ *
+ * \retval PSA_SUCCESS                  When \p alg is a specific algorithm
+ *                                      allowed by the \p policy.
+ * \retval PSA_ERROR_INVALID_ARGUMENT   When \p alg is not a specific algorithm
+ * \retval PSA_ERROR_NOT_PERMITTED      When \p alg is a specific algorithm, but
+ *                                      the \p policy does not allow it.
+ */
+static psa_status_t psa_key_policy_permits( const psa_key_policy_t *policy,
+                                            psa_key_type_t key_type,
+                                            psa_algorithm_t alg )
+{
+    /* '0' is not a valid algorithm */
+    if( alg == 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    /* A requested algorithm cannot be a wildcard. */
+    if( PSA_ALG_IS_WILDCARD( alg ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    if( psa_key_algorithm_permits( key_type, policy->alg, alg ) ||
+        psa_key_algorithm_permits( key_type, policy->alg2, alg ) )
+        return( PSA_SUCCESS );
+    else
+        return( PSA_ERROR_NOT_PERMITTED );
+}
+
+/** Restrict a key policy based on a constraint.
+ *
+ * \note This function requires providing the key type for which the policy is
+ *       being restricted, since some algorithm policy definitions (e.g. MAC)
+ *       have different properties depending on what kind of cipher it is
+ *       combined with.
+ *
+ * \param[in] key_type      The key type for which to restrict the policy
+ * \param[in,out] policy    The policy to restrict.
+ * \param[in] constraint    The policy constraint to apply.
+ *
+ * \retval #PSA_SUCCESS
+ *         \c *policy contains the intersection of the original value of
+ *         \c *policy and \c *constraint.
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ *         \c key_type, \c *policy and \c *constraint are incompatible.
+ *         \c *policy is unchanged.
+ */
+static psa_status_t psa_restrict_key_policy(
+    psa_key_type_t key_type,
+    psa_key_policy_t *policy,
+    const psa_key_policy_t *constraint )
+{
+    psa_algorithm_t intersection_alg =
+        psa_key_policy_algorithm_intersection( key_type, policy->alg,
+                                               constraint->alg );
+    psa_algorithm_t intersection_alg2 =
+        psa_key_policy_algorithm_intersection( key_type, policy->alg2,
+                                               constraint->alg2 );
+    if( intersection_alg == 0 && policy->alg != 0 && constraint->alg != 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    if( intersection_alg2 == 0 && policy->alg2 != 0 && constraint->alg2 != 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    policy->usage &= constraint->usage;
+    policy->alg = intersection_alg;
+    policy->alg2 = intersection_alg2;
+    return( PSA_SUCCESS );
+}
+
+/** Get the description of a key given its identifier and policy constraints
+ *  and lock it.
+ *
+ * The key must have allow all the usage flags set in \p usage. If \p alg is
+ * nonzero, the key must allow operations with this algorithm. If \p alg is
+ * zero, the algorithm is not checked.
+ *
+ * In case of a persistent key, the function loads the description of the key
+ * into a key slot if not already done.
+ *
+ * On success, the returned key slot is locked. It is the responsibility of
+ * the caller to unlock the key slot when it does not access it anymore.
+ */
+static psa_status_t psa_get_and_lock_key_slot_with_policy(
+    mbedtls_svc_key_id_t key,
+    psa_key_slot_t **p_slot,
+    psa_key_usage_t usage,
+    psa_algorithm_t alg )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    status = psa_get_and_lock_key_slot( key, p_slot );
+    if( status != PSA_SUCCESS )
+        return( status );
+    slot = *p_slot;
+
+    /* Enforce that usage policy for the key slot contains all the flags
+     * required by the usage parameter. There is one exception: public
+     * keys can always be exported, so we treat public key objects as
+     * if they had the export flag. */
+    if( PSA_KEY_TYPE_IS_PUBLIC_KEY( slot->attr.type ) )
+        usage &= ~PSA_KEY_USAGE_EXPORT;
+
+    if( ( slot->attr.policy.usage & usage ) != usage )
+    {
+        status = PSA_ERROR_NOT_PERMITTED;
+        goto error;
+    }
+
+    /* Enforce that the usage policy permits the requested algortihm. */
+    if( alg != 0 )
+    {
+        status = psa_key_policy_permits( &slot->attr.policy,
+                                         slot->attr.type,
+                                         alg );
+        if( status != PSA_SUCCESS )
+            goto error;
+    }
+
+    return( PSA_SUCCESS );
+
+error:
+    *p_slot = NULL;
+    psa_unlock_key_slot( slot );
+
+    return( status );
+}
+
+/** Get a key slot containing a transparent key and lock it.
+ *
+ * A transparent key is a key for which the key material is directly
+ * available, as opposed to a key in a secure element.
+ *
+ * This is a temporary function to use instead of
+ * psa_get_and_lock_key_slot_with_policy() until secure element support is
+ * fully implemented.
+ *
+ * On success, the returned key slot is locked. It is the responsibility of the
+ * caller to unlock the key slot when it does not access it anymore.
+ */
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+static psa_status_t psa_get_and_lock_transparent_key_slot_with_policy(
+    mbedtls_svc_key_id_t key,
+    psa_key_slot_t **p_slot,
+    psa_key_usage_t usage,
+    psa_algorithm_t alg )
+{
+    psa_status_t status = psa_get_and_lock_key_slot_with_policy( key, p_slot,
+                                                                 usage, alg );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    if( psa_key_slot_is_external( *p_slot ) )
+    {
+        psa_unlock_key_slot( *p_slot );
+        *p_slot = NULL;
+        return( PSA_ERROR_NOT_SUPPORTED );
+    }
+
+    return( PSA_SUCCESS );
+}
+#else /* MBEDTLS_PSA_CRYPTO_SE_C */
+/* With no secure element support, all keys are transparent. */
+#define psa_get_and_lock_transparent_key_slot_with_policy( key, p_slot, usage, alg )   \
+    psa_get_and_lock_key_slot_with_policy( key, p_slot, usage, alg )
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+psa_status_t psa_remove_key_data_from_memory( psa_key_slot_t *slot )
+{
+    /* Data pointer will always be either a valid pointer or NULL in an
+     * initialized slot, so we can just free it. */
+    if( slot->key.data != NULL )
+        mbedtls_platform_zeroize( slot->key.data, slot->key.bytes);
+
+    mbedtls_free( slot->key.data );
+    slot->key.data = NULL;
+    slot->key.bytes = 0;
+
+    return( PSA_SUCCESS );
+}
+
+/** Completely wipe a slot in memory, including its policy.
+ * Persistent storage is not affected. */
+psa_status_t psa_wipe_key_slot( psa_key_slot_t *slot )
+{
+    psa_status_t status = psa_remove_key_data_from_memory( slot );
+
+    /*
+     * As the return error code may not be handled in case of multiple errors,
+     * do our best to report an unexpected lock counter: if available
+     * call MBEDTLS_PARAM_FAILED that may terminate execution (if called as
+     * part of the execution of a test suite this will stop the test suite
+     * execution).
+     */
+    if( slot->lock_count != 1 )
+    {
+#ifdef MBEDTLS_CHECK_PARAMS
+        MBEDTLS_PARAM_FAILED( slot->lock_count == 1 );
+#endif
+        status = PSA_ERROR_CORRUPTION_DETECTED;
+    }
+
+    /* Multipart operations may still be using the key. This is safe
+     * because all multipart operation objects are independent from
+     * the key slot: if they need to access the key after the setup
+     * phase, they have a copy of the key. Note that this means that
+     * key material can linger until all operations are completed. */
+    /* At this point, key material and other type-specific content has
+     * been wiped. Clear remaining metadata. We can call memset and not
+     * zeroize because the metadata is not particularly sensitive. */
+    memset( slot, 0, sizeof( *slot ) );
+    return( status );
+}
+
+psa_status_t psa_destroy_key( mbedtls_svc_key_id_t key )
+{
+    psa_key_slot_t *slot;
+    psa_status_t status; /* status of the last operation */
+    psa_status_t overall_status = PSA_SUCCESS;
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    psa_se_drv_table_entry_t *driver;
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+    if( mbedtls_svc_key_id_is_null( key ) )
+        return( PSA_SUCCESS );
+
+    /*
+     * Get the description of the key in a key slot. In case of a persistent
+     * key, this will load the key description from persistent memory if not
+     * done yet. We cannot avoid this loading as without it we don't know if
+     * the key is operated by an SE or not and this information is needed by
+     * the current implementation.
+     */
+    status = psa_get_and_lock_key_slot( key, &slot );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    /*
+     * If the key slot containing the key description is under access by the
+     * library (apart from the present access), the key cannot be destroyed
+     * yet. For the time being, just return in error. Eventually (to be
+     * implemented), the key should be destroyed when all accesses have
+     * stopped.
+     */
+    if( slot->lock_count > 1 )
+    {
+       psa_unlock_key_slot( slot );
+       return( PSA_ERROR_GENERIC_ERROR );
+    }
+
+    if( PSA_KEY_LIFETIME_IS_READ_ONLY( slot->attr.lifetime ) )
+    {
+        /* Refuse the destruction of a read-only key (which may or may not work
+         * if we attempt it, depending on whether the key is merely read-only
+         * by policy or actually physically read-only).
+         * Just do the best we can, which is to wipe the copy in memory
+         * (done in this function's cleanup code). */
+        overall_status = PSA_ERROR_NOT_PERMITTED;
+        goto exit;
+    }
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    driver = psa_get_se_driver_entry( slot->attr.lifetime );
+    if( driver != NULL )
+    {
+        /* For a key in a secure element, we need to do three things:
+         * remove the key file in internal storage, destroy the
+         * key inside the secure element, and update the driver's
+         * persistent data. Start a transaction that will encompass these
+         * three actions. */
+        psa_crypto_prepare_transaction( PSA_CRYPTO_TRANSACTION_DESTROY_KEY );
+        psa_crypto_transaction.key.lifetime = slot->attr.lifetime;
+        psa_crypto_transaction.key.slot = psa_key_slot_get_slot_number( slot );
+        psa_crypto_transaction.key.id = slot->attr.id;
+        status = psa_crypto_save_transaction( );
+        if( status != PSA_SUCCESS )
+        {
+            (void) psa_crypto_stop_transaction( );
+            /* We should still try to destroy the key in the secure
+             * element and the key metadata in storage. This is especially
+             * important if the error is that the storage is full.
+             * But how to do it exactly without risking an inconsistent
+             * state after a reset?
+             * https://github.com/ARMmbed/mbed-crypto/issues/215
+             */
+            overall_status = status;
+            goto exit;
+        }
+
+        status = psa_destroy_se_key( driver,
+                                     psa_key_slot_get_slot_number( slot ) );
+        if( overall_status == PSA_SUCCESS )
+            overall_status = status;
+    }
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
+    if( ! PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) )
+    {
+        status = psa_destroy_persistent_key( slot->attr.id );
+        if( overall_status == PSA_SUCCESS )
+            overall_status = status;
+
+        /* TODO: other slots may have a copy of the same key. We should
+         * invalidate them.
+         * https://github.com/ARMmbed/mbed-crypto/issues/214
+         */
+    }
+#endif /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    if( driver != NULL )
+    {
+        status = psa_save_se_persistent_data( driver );
+        if( overall_status == PSA_SUCCESS )
+            overall_status = status;
+        status = psa_crypto_stop_transaction( );
+        if( overall_status == PSA_SUCCESS )
+            overall_status = status;
+    }
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+exit:
+    status = psa_wipe_key_slot( slot );
+    /* Prioritize CORRUPTION_DETECTED from wiping over a storage error */
+    if( status != PSA_SUCCESS )
+        overall_status = status;
+    return( overall_status );
+}
+
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY)
+static psa_status_t psa_get_rsa_public_exponent(
+    const mbedtls_rsa_context *rsa,
+    psa_key_attributes_t *attributes )
+{
+    mbedtls_mpi mpi;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    uint8_t *buffer = NULL;
+    size_t buflen;
+    mbedtls_mpi_init( &mpi );
+
+    ret = mbedtls_rsa_export( rsa, NULL, NULL, NULL, NULL, &mpi );
+    if( ret != 0 )
+        goto exit;
+    if( mbedtls_mpi_cmp_int( &mpi, 65537 ) == 0 )
+    {
+        /* It's the default value, which is reported as an empty string,
+         * so there's nothing to do. */
+        goto exit;
+    }
+
+    buflen = mbedtls_mpi_size( &mpi );
+    buffer = mbedtls_calloc( 1, buflen );
+    if( buffer == NULL )
+    {
+        ret = MBEDTLS_ERR_MPI_ALLOC_FAILED;
+        goto exit;
+    }
+    ret = mbedtls_mpi_write_binary( &mpi, buffer, buflen );
+    if( ret != 0 )
+        goto exit;
+    attributes->domain_parameters = buffer;
+    attributes->domain_parameters_size = buflen;
+
+exit:
+    mbedtls_mpi_free( &mpi );
+    if( ret != 0 )
+        mbedtls_free( buffer );
+    return( mbedtls_to_psa_error( ret ) );
+}
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */
+
+/** Retrieve all the publicly-accessible attributes of a key.
+ */
+psa_status_t psa_get_key_attributes( mbedtls_svc_key_id_t key,
+                                     psa_key_attributes_t *attributes )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    psa_reset_key_attributes( attributes );
+
+    status = psa_get_and_lock_key_slot_with_policy( key, &slot, 0, 0 );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    attributes->core = slot->attr;
+    attributes->core.flags &= ( MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY |
+                                MBEDTLS_PSA_KA_MASK_DUAL_USE );
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    if( psa_key_slot_is_external( slot ) )
+        psa_set_key_slot_number( attributes,
+                                 psa_key_slot_get_slot_number( slot ) );
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+    switch( slot->attr.type )
+    {
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY)
+        case PSA_KEY_TYPE_RSA_KEY_PAIR:
+        case PSA_KEY_TYPE_RSA_PUBLIC_KEY:
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+            /* TODO: reporting the public exponent for opaque keys
+             * is not yet implemented.
+             * https://github.com/ARMmbed/mbed-crypto/issues/216
+             */
+            if( psa_key_slot_is_external( slot ) )
+                break;
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+            {
+                mbedtls_rsa_context *rsa = NULL;
+
+                status = mbedtls_psa_rsa_load_representation(
+                             slot->attr.type,
+                             slot->key.data,
+                             slot->key.bytes,
+                             &rsa );
+                if( status != PSA_SUCCESS )
+                    break;
+
+                status = psa_get_rsa_public_exponent( rsa,
+                                                      attributes );
+                mbedtls_rsa_free( rsa );
+                mbedtls_free( rsa );
+            }
+            break;
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */
+        default:
+            /* Nothing else to do. */
+            break;
+    }
+
+    if( status != PSA_SUCCESS )
+        psa_reset_key_attributes( attributes );
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+psa_status_t psa_get_key_slot_number(
+    const psa_key_attributes_t *attributes,
+    psa_key_slot_number_t *slot_number )
+{
+    if( attributes->core.flags & MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER )
+    {
+        *slot_number = attributes->slot_number;
+        return( PSA_SUCCESS );
+    }
+    else
+        return( PSA_ERROR_INVALID_ARGUMENT );
+}
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+static psa_status_t psa_export_key_buffer_internal( const uint8_t *key_buffer,
+                                                    size_t key_buffer_size,
+                                                    uint8_t *data,
+                                                    size_t data_size,
+                                                    size_t *data_length )
+{
+    if( key_buffer_size > data_size )
+        return( PSA_ERROR_BUFFER_TOO_SMALL );
+    memcpy( data, key_buffer, key_buffer_size );
+    memset( data + key_buffer_size, 0,
+            data_size - key_buffer_size );
+    *data_length = key_buffer_size;
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_export_key_internal(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    uint8_t *data, size_t data_size, size_t *data_length )
+{
+    psa_key_type_t type = attributes->core.type;
+
+    if( key_type_is_raw_bytes( type ) ||
+        PSA_KEY_TYPE_IS_RSA( type )   ||
+        PSA_KEY_TYPE_IS_ECC( type )      )
+    {
+        return( psa_export_key_buffer_internal(
+                    key_buffer, key_buffer_size,
+                    data, data_size, data_length ) );
+    }
+    else
+    {
+        /* This shouldn't happen in the reference implementation, but
+           it is valid for a special-purpose implementation to omit
+           support for exporting certain key types. */
+        return( PSA_ERROR_NOT_SUPPORTED );
+    }
+}
+
+psa_status_t psa_export_key( mbedtls_svc_key_id_t key,
+                             uint8_t *data,
+                             size_t data_size,
+                             size_t *data_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    /* Reject a zero-length output buffer now, since this can never be a
+     * valid key representation. This way we know that data must be a valid
+     * pointer and we can do things like memset(data, ..., data_size). */
+    if( data_size == 0 )
+        return( PSA_ERROR_BUFFER_TOO_SMALL );
+
+    /* Set the key to empty now, so that even when there are errors, we always
+     * set data_length to a value between 0 and data_size. On error, setting
+     * the key to empty is a good choice because an empty key representation is
+     * unlikely to be accepted anywhere. */
+    *data_length = 0;
+
+    /* Export requires the EXPORT flag. There is an exception for public keys,
+     * which don't require any flag, but
+     * psa_get_and_lock_key_slot_with_policy() takes care of this.
+     */
+    status = psa_get_and_lock_key_slot_with_policy( key, &slot,
+                                                    PSA_KEY_USAGE_EXPORT, 0 );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    psa_key_attributes_t attributes = {
+        .core = slot->attr
+    };
+    status = psa_driver_wrapper_export_key( &attributes,
+                 slot->key.data, slot->key.bytes,
+                 data, data_size, data_length );
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+psa_status_t psa_export_public_key_internal(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer,
+    size_t key_buffer_size,
+    uint8_t *data,
+    size_t data_size,
+    size_t *data_length )
+{
+    psa_key_type_t type = attributes->core.type;
+
+    if( PSA_KEY_TYPE_IS_RSA( type ) || PSA_KEY_TYPE_IS_ECC( type ) )
+    {
+        if( PSA_KEY_TYPE_IS_PUBLIC_KEY( type ) )
+        {
+            /* Exporting public -> public */
+            return( psa_export_key_buffer_internal(
+                        key_buffer, key_buffer_size,
+                        data, data_size, data_length ) );
+        }
+
+        if( PSA_KEY_TYPE_IS_RSA( type ) )
+        {
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY)
+            return( mbedtls_psa_rsa_export_public_key( attributes,
+                                                       key_buffer,
+                                                       key_buffer_size,
+                                                       data,
+                                                       data_size,
+                                                       data_length ) );
+#else
+            /* We don't know how to convert a private RSA key to public. */
+            return( PSA_ERROR_NOT_SUPPORTED );
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */
+        }
+        else
+        {
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY)
+            return( mbedtls_psa_ecp_export_public_key( attributes,
+                                                       key_buffer,
+                                                       key_buffer_size,
+                                                       data,
+                                                       data_size,
+                                                       data_length ) );
+#else
+            /* We don't know how to convert a private ECC key to public */
+            return( PSA_ERROR_NOT_SUPPORTED );
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY) */
+        }
+    }
+    else
+    {
+        /* This shouldn't happen in the reference implementation, but
+           it is valid for a special-purpose implementation to omit
+           support for exporting certain key types. */
+        return( PSA_ERROR_NOT_SUPPORTED );
+    }
+}
+
+psa_status_t psa_export_public_key( mbedtls_svc_key_id_t key,
+                                    uint8_t *data,
+                                    size_t data_size,
+                                    size_t *data_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    /* Reject a zero-length output buffer now, since this can never be a
+     * valid key representation. This way we know that data must be a valid
+     * pointer and we can do things like memset(data, ..., data_size). */
+    if( data_size == 0 )
+        return( PSA_ERROR_BUFFER_TOO_SMALL );
+
+    /* Set the key to empty now, so that even when there are errors, we always
+     * set data_length to a value between 0 and data_size. On error, setting
+     * the key to empty is a good choice because an empty key representation is
+     * unlikely to be accepted anywhere. */
+    *data_length = 0;
+
+    /* Exporting a public key doesn't require a usage flag. */
+    status = psa_get_and_lock_key_slot_with_policy( key, &slot, 0, 0 );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    if( ! PSA_KEY_TYPE_IS_ASYMMETRIC( slot->attr.type ) )
+    {
+         status = PSA_ERROR_INVALID_ARGUMENT;
+         goto exit;
+    }
+
+    psa_key_attributes_t attributes = {
+        .core = slot->attr
+    };
+    status = psa_driver_wrapper_export_public_key(
+        &attributes, slot->key.data, slot->key.bytes,
+        data, data_size, data_length );
+
+exit:
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+#if defined(static_assert)
+static_assert( ( MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_DUAL_USE ) == 0,
+               "One or more key attribute flag is listed as both external-only and dual-use" );
+static_assert( ( PSA_KA_MASK_INTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_DUAL_USE ) == 0,
+               "One or more key attribute flag is listed as both internal-only and dual-use" );
+static_assert( ( PSA_KA_MASK_INTERNAL_ONLY & MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY ) == 0,
+               "One or more key attribute flag is listed as both internal-only and external-only" );
+#endif
+
+/** Validate that a key policy is internally well-formed.
+ *
+ * This function only rejects invalid policies. It does not validate the
+ * consistency of the policy with respect to other attributes of the key
+ * such as the key type.
+ */
+static psa_status_t psa_validate_key_policy( const psa_key_policy_t *policy )
+{
+    if( ( policy->usage & ~( PSA_KEY_USAGE_EXPORT |
+                             PSA_KEY_USAGE_COPY |
+                             PSA_KEY_USAGE_ENCRYPT |
+                             PSA_KEY_USAGE_DECRYPT |
+                             PSA_KEY_USAGE_SIGN_MESSAGE |
+                             PSA_KEY_USAGE_VERIFY_MESSAGE |
+                             PSA_KEY_USAGE_SIGN_HASH |
+                             PSA_KEY_USAGE_VERIFY_HASH |
+                             PSA_KEY_USAGE_DERIVE ) ) != 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    return( PSA_SUCCESS );
+}
+
+/** Validate the internal consistency of key attributes.
+ *
+ * This function only rejects invalid attribute values. If does not
+ * validate the consistency of the attributes with any key data that may
+ * be involved in the creation of the key.
+ *
+ * Call this function early in the key creation process.
+ *
+ * \param[in] attributes    Key attributes for the new key.
+ * \param[out] p_drv        On any return, the driver for the key, if any.
+ *                          NULL for a transparent key.
+ *
+ */
+static psa_status_t psa_validate_key_attributes(
+    const psa_key_attributes_t *attributes,
+    psa_se_drv_table_entry_t **p_drv )
+{
+    psa_status_t status = PSA_ERROR_INVALID_ARGUMENT;
+    psa_key_lifetime_t lifetime = psa_get_key_lifetime( attributes );
+    mbedtls_svc_key_id_t key = psa_get_key_id( attributes );
+
+    status = psa_validate_key_location( lifetime, p_drv );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    status = psa_validate_key_persistence( lifetime );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    if ( PSA_KEY_LIFETIME_IS_VOLATILE( lifetime ) )
+    {
+        if( MBEDTLS_SVC_KEY_ID_GET_KEY_ID( key ) != 0 )
+            return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+    else
+    {
+        if( !psa_is_valid_key_id( psa_get_key_id( attributes ), 0 ) )
+            return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+
+    status = psa_validate_key_policy( &attributes->core.policy );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    /* Refuse to create overly large keys.
+     * Note that this doesn't trigger on import if the attributes don't
+     * explicitly specify a size (so psa_get_key_bits returns 0), so
+     * psa_import_key() needs its own checks. */
+    if( psa_get_key_bits( attributes ) > PSA_MAX_KEY_BITS )
+        return( PSA_ERROR_NOT_SUPPORTED );
+
+    /* Reject invalid flags. These should not be reachable through the API. */
+    if( attributes->core.flags & ~ ( MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY |
+                                     MBEDTLS_PSA_KA_MASK_DUAL_USE ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    return( PSA_SUCCESS );
+}
+
+/** Prepare a key slot to receive key material.
+ *
+ * This function allocates a key slot and sets its metadata.
+ *
+ * If this function fails, call psa_fail_key_creation().
+ *
+ * This function is intended to be used as follows:
+ * -# Call psa_start_key_creation() to allocate a key slot, prepare
+ *    it with the specified attributes, and in case of a volatile key assign it
+ *    a volatile key identifier.
+ * -# Populate the slot with the key material.
+ * -# Call psa_finish_key_creation() to finalize the creation of the slot.
+ * In case of failure at any step, stop the sequence and call
+ * psa_fail_key_creation().
+ *
+ * On success, the key slot is locked. It is the responsibility of the caller
+ * to unlock the key slot when it does not access it anymore.
+ *
+ * \param method            An identification of the calling function.
+ * \param[in] attributes    Key attributes for the new key.
+ * \param[out] p_slot       On success, a pointer to the prepared slot.
+ * \param[out] p_drv        On any return, the driver for the key, if any.
+ *                          NULL for a transparent key.
+ *
+ * \retval #PSA_SUCCESS
+ *         The key slot is ready to receive key material.
+ * \return If this function fails, the key slot is an invalid state.
+ *         You must call psa_fail_key_creation() to wipe and free the slot.
+ */
+static psa_status_t psa_start_key_creation(
+    psa_key_creation_method_t method,
+    const psa_key_attributes_t *attributes,
+    psa_key_slot_t **p_slot,
+    psa_se_drv_table_entry_t **p_drv )
+{
+    psa_status_t status;
+    psa_key_id_t volatile_key_id;
+    psa_key_slot_t *slot;
+
+    (void) method;
+    *p_drv = NULL;
+
+    status = psa_validate_key_attributes( attributes, p_drv );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    status = psa_get_empty_key_slot( &volatile_key_id, p_slot );
+    if( status != PSA_SUCCESS )
+        return( status );
+    slot = *p_slot;
+
+    /* We're storing the declared bit-size of the key. It's up to each
+     * creation mechanism to verify that this information is correct.
+     * It's automatically correct for mechanisms that use the bit-size as
+     * an input (generate, device) but not for those where the bit-size
+     * is optional (import, copy). In case of a volatile key, assign it the
+     * volatile key identifier associated to the slot returned to contain its
+     * definition. */
+
+    slot->attr = attributes->core;
+    if( PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) )
+    {
+#if !defined(MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER)
+        slot->attr.id = volatile_key_id;
+#else
+        slot->attr.id.key_id = volatile_key_id;
+#endif
+    }
+
+    /* Erase external-only flags from the internal copy. To access
+     * external-only flags, query `attributes`. Thanks to the check
+     * in psa_validate_key_attributes(), this leaves the dual-use
+     * flags and any internal flag that psa_get_empty_key_slot()
+     * may have set. */
+    slot->attr.flags &= ~MBEDTLS_PSA_KA_MASK_EXTERNAL_ONLY;
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    /* For a key in a secure element, we need to do three things
+     * when creating or registering a persistent key:
+     * create the key file in internal storage, create the
+     * key inside the secure element, and update the driver's
+     * persistent data. This is done by starting a transaction that will
+     * encompass these three actions.
+     * For registering a volatile key, we just need to find an appropriate
+     * slot number inside the SE. Since the key is designated volatile, creating
+     * a transaction is not required. */
+    /* The first thing to do is to find a slot number for the new key.
+     * We save the slot number in persistent storage as part of the
+     * transaction data. It will be needed to recover if the power
+     * fails during the key creation process, to clean up on the secure
+     * element side after restarting. Obtaining a slot number from the
+     * secure element driver updates its persistent state, but we do not yet
+     * save the driver's persistent state, so that if the power fails,
+     * we can roll back to a state where the key doesn't exist. */
+    if( *p_drv != NULL )
+    {
+        psa_key_slot_number_t slot_number;
+        status = psa_find_se_slot_for_key( attributes, method, *p_drv,
+                                           &slot_number );
+        if( status != PSA_SUCCESS )
+            return( status );
+
+        if( ! PSA_KEY_LIFETIME_IS_VOLATILE( attributes->core.lifetime ) )
+        {
+            psa_crypto_prepare_transaction( PSA_CRYPTO_TRANSACTION_CREATE_KEY );
+            psa_crypto_transaction.key.lifetime = slot->attr.lifetime;
+            psa_crypto_transaction.key.slot = slot_number;
+            psa_crypto_transaction.key.id = slot->attr.id;
+            status = psa_crypto_save_transaction( );
+            if( status != PSA_SUCCESS )
+            {
+                (void) psa_crypto_stop_transaction( );
+                return( status );
+            }
+        }
+
+        status = psa_copy_key_material_into_slot(
+            slot, (uint8_t *)( &slot_number ), sizeof( slot_number ) );
+    }
+
+    if( *p_drv == NULL && method == PSA_KEY_CREATION_REGISTER )
+    {
+        /* Key registration only makes sense with a secure element. */
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+    return( PSA_SUCCESS );
+}
+
+/** Finalize the creation of a key once its key material has been set.
+ *
+ * This entails writing the key to persistent storage.
+ *
+ * If this function fails, call psa_fail_key_creation().
+ * See the documentation of psa_start_key_creation() for the intended use
+ * of this function.
+ *
+ * If the finalization succeeds, the function unlocks the key slot (it was
+ * locked by psa_start_key_creation()) and the key slot cannot be accessed
+ * anymore as part of the key creation process.
+ *
+ * \param[in,out] slot  Pointer to the slot with key material.
+ * \param[in] driver    The secure element driver for the key,
+ *                      or NULL for a transparent key.
+ * \param[out] key      On success, identifier of the key. Note that the
+ *                      key identifier is also stored in the key slot.
+ *
+ * \retval #PSA_SUCCESS
+ *         The key was successfully created.
+ * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
+ * \retval #PSA_ERROR_INSUFFICIENT_STORAGE
+ * \retval #PSA_ERROR_ALREADY_EXISTS
+ * \retval #PSA_ERROR_DATA_INVALID
+ * \retval #PSA_ERROR_DATA_CORRUPT
+ * \retval #PSA_ERROR_STORAGE_FAILURE
+ *
+ * \return If this function fails, the key slot is an invalid state.
+ *         You must call psa_fail_key_creation() to wipe and free the slot.
+ */
+static psa_status_t psa_finish_key_creation(
+    psa_key_slot_t *slot,
+    psa_se_drv_table_entry_t *driver,
+    mbedtls_svc_key_id_t *key)
+{
+    psa_status_t status = PSA_SUCCESS;
+    (void) slot;
+    (void) driver;
+
+#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
+    if( ! PSA_KEY_LIFETIME_IS_VOLATILE( slot->attr.lifetime ) )
+    {
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+        if( driver != NULL )
+        {
+            psa_se_key_data_storage_t data;
+            psa_key_slot_number_t slot_number =
+                psa_key_slot_get_slot_number( slot ) ;
+
+#if defined(static_assert)
+            static_assert( sizeof( slot_number ) ==
+                           sizeof( data.slot_number ),
+                           "Slot number size does not match psa_se_key_data_storage_t" );
+#endif
+            memcpy( &data.slot_number, &slot_number, sizeof( slot_number ) );
+            status = psa_save_persistent_key( &slot->attr,
+                                              (uint8_t*) &data,
+                                              sizeof( data ) );
+        }
+        else
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+        {
+            /* Key material is saved in export representation in the slot, so
+             * just pass the slot buffer for storage. */
+            status = psa_save_persistent_key( &slot->attr,
+                                              slot->key.data,
+                                              slot->key.bytes );
+        }
+    }
+#endif /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    /* Finish the transaction for a key creation. This does not
+     * happen when registering an existing key. Detect this case
+     * by checking whether a transaction is in progress (actual
+     * creation of a persistent key in a secure element requires a transaction,
+     * but registration or volatile key creation doesn't use one). */
+    if( driver != NULL &&
+        psa_crypto_transaction.unknown.type == PSA_CRYPTO_TRANSACTION_CREATE_KEY )
+    {
+        status = psa_save_se_persistent_data( driver );
+        if( status != PSA_SUCCESS )
+        {
+            psa_destroy_persistent_key( slot->attr.id );
+            return( status );
+        }
+        status = psa_crypto_stop_transaction( );
+    }
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+    if( status == PSA_SUCCESS )
+    {
+        *key = slot->attr.id;
+        status = psa_unlock_key_slot( slot );
+        if( status != PSA_SUCCESS )
+            *key = MBEDTLS_SVC_KEY_ID_INIT;
+    }
+
+    return( status );
+}
+
+/** Abort the creation of a key.
+ *
+ * You may call this function after calling psa_start_key_creation(),
+ * or after psa_finish_key_creation() fails. In other circumstances, this
+ * function may not clean up persistent storage.
+ * See the documentation of psa_start_key_creation() for the intended use
+ * of this function.
+ *
+ * \param[in,out] slot  Pointer to the slot with key material.
+ * \param[in] driver    The secure element driver for the key,
+ *                      or NULL for a transparent key.
+ */
+static void psa_fail_key_creation( psa_key_slot_t *slot,
+                                   psa_se_drv_table_entry_t *driver )
+{
+    (void) driver;
+
+    if( slot == NULL )
+        return;
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    /* TODO: If the key has already been created in the secure
+     * element, and the failure happened later (when saving metadata
+     * to internal storage), we need to destroy the key in the secure
+     * element.
+     * https://github.com/ARMmbed/mbed-crypto/issues/217
+     */
+
+    /* Abort the ongoing transaction if any (there may not be one if
+     * the creation process failed before starting one, or if the
+     * key creation is a registration of a key in a secure element).
+     * Earlier functions must already have done what it takes to undo any
+     * partial creation. All that's left is to update the transaction data
+     * itself. */
+    (void) psa_crypto_stop_transaction( );
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+    psa_wipe_key_slot( slot );
+}
+
+/** Validate optional attributes during key creation.
+ *
+ * Some key attributes are optional during key creation. If they are
+ * specified in the attributes structure, check that they are consistent
+ * with the data in the slot.
+ *
+ * This function should be called near the end of key creation, after
+ * the slot in memory is fully populated but before saving persistent data.
+ */
+static psa_status_t psa_validate_optional_attributes(
+    const psa_key_slot_t *slot,
+    const psa_key_attributes_t *attributes )
+{
+    if( attributes->core.type != 0 )
+    {
+        if( attributes->core.type != slot->attr.type )
+            return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+
+    if( attributes->domain_parameters_size != 0 )
+    {
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY)
+        if( PSA_KEY_TYPE_IS_RSA( slot->attr.type ) )
+        {
+            mbedtls_rsa_context *rsa = NULL;
+            mbedtls_mpi actual, required;
+            int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+            psa_status_t status = mbedtls_psa_rsa_load_representation(
+                                      slot->attr.type,
+                                      slot->key.data,
+                                      slot->key.bytes,
+                                      &rsa );
+            if( status != PSA_SUCCESS )
+                return( status );
+
+            mbedtls_mpi_init( &actual );
+            mbedtls_mpi_init( &required );
+            ret = mbedtls_rsa_export( rsa,
+                                      NULL, NULL, NULL, NULL, &actual );
+            mbedtls_rsa_free( rsa );
+            mbedtls_free( rsa );
+            if( ret != 0 )
+                goto rsa_exit;
+            ret = mbedtls_mpi_read_binary( &required,
+                                           attributes->domain_parameters,
+                                           attributes->domain_parameters_size );
+            if( ret != 0 )
+                goto rsa_exit;
+            if( mbedtls_mpi_cmp_mpi( &actual, &required ) != 0 )
+                ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
+        rsa_exit:
+            mbedtls_mpi_free( &actual );
+            mbedtls_mpi_free( &required );
+            if( ret != 0)
+                return( mbedtls_to_psa_error( ret ) );
+        }
+        else
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */
+        {
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        }
+    }
+
+    if( attributes->core.bits != 0 )
+    {
+        if( attributes->core.bits != slot->attr.bits )
+            return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_import_key( const psa_key_attributes_t *attributes,
+                             const uint8_t *data,
+                             size_t data_length,
+                             mbedtls_svc_key_id_t *key )
+{
+    psa_status_t status;
+    psa_key_slot_t *slot = NULL;
+    psa_se_drv_table_entry_t *driver = NULL;
+    size_t bits;
+
+    *key = MBEDTLS_SVC_KEY_ID_INIT;
+
+    /* Reject zero-length symmetric keys (including raw data key objects).
+     * This also rejects any key which might be encoded as an empty string,
+     * which is never valid. */
+    if( data_length == 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    status = psa_start_key_creation( PSA_KEY_CREATION_IMPORT, attributes,
+                                     &slot, &driver );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    /* In the case of a transparent key or an opaque key stored in local
+     * storage (thus not in the case of generating a key in a secure element
+     * or cryptoprocessor with storage), we have to allocate a buffer to
+     * hold the generated key material. */
+    if( slot->key.data == NULL )
+    {
+        status = psa_allocate_buffer_to_slot( slot, data_length );
+        if( status != PSA_SUCCESS )
+            goto exit;
+    }
+
+    bits = slot->attr.bits;
+    status = psa_driver_wrapper_import_key( attributes,
+                                            data, data_length,
+                                            slot->key.data,
+                                            slot->key.bytes,
+                                            &slot->key.bytes, &bits );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    if( slot->attr.bits == 0 )
+        slot->attr.bits = (psa_key_bits_t) bits;
+    else if( bits != slot->attr.bits )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+    status = psa_validate_optional_attributes( slot, attributes );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_finish_key_creation( slot, driver, key );
+exit:
+    if( status != PSA_SUCCESS )
+        psa_fail_key_creation( slot, driver );
+
+    return( status );
+}
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+psa_status_t mbedtls_psa_register_se_key(
+    const psa_key_attributes_t *attributes )
+{
+    psa_status_t status;
+    psa_key_slot_t *slot = NULL;
+    psa_se_drv_table_entry_t *driver = NULL;
+    mbedtls_svc_key_id_t key = MBEDTLS_SVC_KEY_ID_INIT;
+
+    /* Leaving attributes unspecified is not currently supported.
+     * It could make sense to query the key type and size from the
+     * secure element, but not all secure elements support this
+     * and the driver HAL doesn't currently support it. */
+    if( psa_get_key_type( attributes ) == PSA_KEY_TYPE_NONE )
+        return( PSA_ERROR_NOT_SUPPORTED );
+    if( psa_get_key_bits( attributes ) == 0 )
+        return( PSA_ERROR_NOT_SUPPORTED );
+
+    status = psa_start_key_creation( PSA_KEY_CREATION_REGISTER, attributes,
+                                     &slot, &driver );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_finish_key_creation( slot, driver, &key );
+
+exit:
+    if( status != PSA_SUCCESS )
+        psa_fail_key_creation( slot, driver );
+
+    /* Registration doesn't keep the key in RAM. */
+    psa_close_key( key );
+    return( status );
+}
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+static psa_status_t psa_copy_key_material( const psa_key_slot_t *source,
+                                           psa_key_slot_t *target )
+{
+    psa_status_t status = psa_copy_key_material_into_slot( target,
+                                                           source->key.data,
+                                                           source->key.bytes );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    target->attr.type = source->attr.type;
+    target->attr.bits = source->attr.bits;
+
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_copy_key( mbedtls_svc_key_id_t source_key,
+                           const psa_key_attributes_t *specified_attributes,
+                           mbedtls_svc_key_id_t *target_key )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *source_slot = NULL;
+    psa_key_slot_t *target_slot = NULL;
+    psa_key_attributes_t actual_attributes = *specified_attributes;
+    psa_se_drv_table_entry_t *driver = NULL;
+
+    *target_key = MBEDTLS_SVC_KEY_ID_INIT;
+
+    status = psa_get_and_lock_transparent_key_slot_with_policy(
+                 source_key, &source_slot, PSA_KEY_USAGE_COPY, 0 );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_validate_optional_attributes( source_slot,
+                                               specified_attributes );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_restrict_key_policy( source_slot->attr.type,
+                                      &actual_attributes.core.policy,
+                                      &source_slot->attr.policy );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_start_key_creation( PSA_KEY_CREATION_COPY, &actual_attributes,
+                                     &target_slot, &driver );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    if( driver != NULL )
+    {
+        /* Copying to a secure element is not implemented yet. */
+        status = PSA_ERROR_NOT_SUPPORTED;
+        goto exit;
+    }
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+    if( psa_key_lifetime_is_external( actual_attributes.core.lifetime ) )
+    {
+        /*
+         * Copying through an opaque driver is not implemented yet, consider
+         * a lifetime with an external location as an invalid parameter for
+         * now.
+         */
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+    status = psa_copy_key_material( source_slot, target_slot );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_finish_key_creation( target_slot, driver, target_key );
+exit:
+    if( status != PSA_SUCCESS )
+        psa_fail_key_creation( target_slot, driver );
+
+    unlock_status = psa_unlock_key_slot( source_slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+
+
+/****************************************************************/
+/* Message digests */
+/****************************************************************/
+
+psa_status_t psa_hash_abort( psa_hash_operation_t *operation )
+{
+    /* Aborting a non-active operation is allowed */
+    if( operation->id == 0 )
+        return( PSA_SUCCESS );
+
+    psa_status_t status = psa_driver_wrapper_hash_abort( operation );
+    operation->id = 0;
+
+    return( status );
+}
+
+psa_status_t psa_hash_setup( psa_hash_operation_t *operation,
+                             psa_algorithm_t alg )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    /* A context must be freshly initialized before it can be set up. */
+    if( operation->id != 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( !PSA_ALG_IS_HASH( alg ) )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+    /* Ensure all of the context is zeroized, since PSA_HASH_OPERATION_INIT only
+     * directly zeroes the int-sized dummy member of the context union. */
+    memset( &operation->ctx, 0, sizeof( operation->ctx ) );
+
+    status = psa_driver_wrapper_hash_setup( operation, alg );
+
+exit:
+    if( status != PSA_SUCCESS )
+        psa_hash_abort( operation );
+
+    return status;
+}
+
+psa_status_t psa_hash_update( psa_hash_operation_t *operation,
+                              const uint8_t *input,
+                              size_t input_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    if( operation->id == 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    /* Don't require hash implementations to behave correctly on a
+     * zero-length input, which may have an invalid pointer. */
+    if( input_length == 0 )
+        return( PSA_SUCCESS );
+
+    status = psa_driver_wrapper_hash_update( operation, input, input_length );
+
+exit:
+    if( status != PSA_SUCCESS )
+        psa_hash_abort( operation );
+
+    return( status );
+}
+
+psa_status_t psa_hash_finish( psa_hash_operation_t *operation,
+                              uint8_t *hash,
+                              size_t hash_size,
+                              size_t *hash_length )
+{
+    *hash_length = 0;
+    if( operation->id == 0 )
+        return( PSA_ERROR_BAD_STATE );
+
+    psa_status_t status = psa_driver_wrapper_hash_finish(
+                            operation, hash, hash_size, hash_length );
+    psa_hash_abort( operation );
+    return( status );
+}
+
+psa_status_t psa_hash_verify( psa_hash_operation_t *operation,
+                              const uint8_t *hash,
+                              size_t hash_length )
+{
+    uint8_t actual_hash[MBEDTLS_MD_MAX_SIZE];
+    size_t actual_hash_length;
+    psa_status_t status = psa_hash_finish(
+                            operation,
+                            actual_hash, sizeof( actual_hash ),
+                            &actual_hash_length );
+
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    if( actual_hash_length != hash_length )
+    {
+        status = PSA_ERROR_INVALID_SIGNATURE;
+        goto exit;
+    }
+
+    if( mbedtls_psa_safer_memcmp( hash, actual_hash, actual_hash_length ) != 0 )
+        status = PSA_ERROR_INVALID_SIGNATURE;
+
+exit:
+    if( status != PSA_SUCCESS )
+        psa_hash_abort(operation);
+
+    return( status );
+}
+
+psa_status_t psa_hash_compute( psa_algorithm_t alg,
+                               const uint8_t *input, size_t input_length,
+                               uint8_t *hash, size_t hash_size,
+                               size_t *hash_length )
+{
+    *hash_length = 0;
+    if( !PSA_ALG_IS_HASH( alg ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    return( psa_driver_wrapper_hash_compute( alg, input, input_length,
+                                             hash, hash_size, hash_length ) );
+}
+
+psa_status_t psa_hash_compare( psa_algorithm_t alg,
+                               const uint8_t *input, size_t input_length,
+                               const uint8_t *hash, size_t hash_length )
+{
+    uint8_t actual_hash[MBEDTLS_MD_MAX_SIZE];
+    size_t actual_hash_length;
+
+    if( !PSA_ALG_IS_HASH( alg ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    psa_status_t status = psa_driver_wrapper_hash_compute(
+                            alg, input, input_length,
+                            actual_hash, sizeof(actual_hash),
+                            &actual_hash_length );
+    if( status != PSA_SUCCESS )
+        return( status );
+    if( actual_hash_length != hash_length )
+        return( PSA_ERROR_INVALID_SIGNATURE );
+    if( mbedtls_psa_safer_memcmp( hash, actual_hash, actual_hash_length ) != 0 )
+        return( PSA_ERROR_INVALID_SIGNATURE );
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_hash_clone( const psa_hash_operation_t *source_operation,
+                             psa_hash_operation_t *target_operation )
+{
+    if( source_operation->id == 0 ||
+        target_operation->id != 0 )
+    {
+        return( PSA_ERROR_BAD_STATE );
+    }
+
+    psa_status_t status = psa_driver_wrapper_hash_clone( source_operation,
+                                                         target_operation );
+    if( status != PSA_SUCCESS )
+        psa_hash_abort( target_operation );
+
+    return( status );
+}
+
+
+/****************************************************************/
+/* MAC */
+/****************************************************************/
+
+psa_status_t psa_mac_abort( psa_mac_operation_t *operation )
+{
+    /* Aborting a non-active operation is allowed */
+    if( operation->id == 0 )
+        return( PSA_SUCCESS );
+
+    psa_status_t status = psa_driver_wrapper_mac_abort( operation );
+    operation->mac_size = 0;
+    operation->is_sign = 0;
+    operation->id = 0;
+
+    return( status );
+}
+
+static psa_status_t psa_mac_finalize_alg_and_key_validation(
+    psa_algorithm_t alg,
+    const psa_key_attributes_t *attributes,
+    uint8_t *mac_size )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_type_t key_type = psa_get_key_type( attributes );
+    size_t key_bits = psa_get_key_bits( attributes );
+
+    if( ! PSA_ALG_IS_MAC( alg ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    /* Validate the combination of key type and algorithm */
+    status = psa_mac_key_can_do( alg, key_type );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    /* Get the output length for the algorithm and key combination */
+    *mac_size = PSA_MAC_LENGTH( key_type, key_bits, alg );
+
+    if( *mac_size < 4 )
+    {
+        /* A very short MAC is too short for security since it can be
+         * brute-forced. Ancient protocols with 32-bit MACs do exist,
+         * so we make this our minimum, even though 32 bits is still
+         * too small for security. */
+        return( PSA_ERROR_NOT_SUPPORTED );
+    }
+
+    if( *mac_size > PSA_MAC_LENGTH( key_type, key_bits,
+                                    PSA_ALG_FULL_LENGTH_MAC( alg ) ) )
+    {
+        /* It's impossible to "truncate" to a larger length than the full length
+         * of the algorithm. */
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+
+    return( PSA_SUCCESS );
+}
+
+static psa_status_t psa_mac_setup( psa_mac_operation_t *operation,
+                                   mbedtls_svc_key_id_t key,
+                                   psa_algorithm_t alg,
+                                   int is_sign )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot = NULL;
+
+    /* A context must be freshly initialized before it can be set up. */
+    if( operation->id != 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    status = psa_get_and_lock_key_slot_with_policy(
+                 key,
+                 &slot,
+                 is_sign ? PSA_KEY_USAGE_SIGN_HASH : PSA_KEY_USAGE_VERIFY_HASH,
+                 alg );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    psa_key_attributes_t attributes = {
+        .core = slot->attr
+    };
+
+    status = psa_mac_finalize_alg_and_key_validation( alg, &attributes,
+                                                      &operation->mac_size );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    operation->is_sign = is_sign;
+    /* Dispatch the MAC setup call with validated input */
+    if( is_sign )
+    {
+        status = psa_driver_wrapper_mac_sign_setup( operation,
+                                                    &attributes,
+                                                    slot->key.data,
+                                                    slot->key.bytes,
+                                                    alg );
+    }
+    else
+    {
+        status = psa_driver_wrapper_mac_verify_setup( operation,
+                                                      &attributes,
+                                                      slot->key.data,
+                                                      slot->key.bytes,
+                                                      alg );
+    }
+
+exit:
+    if( status != PSA_SUCCESS )
+        psa_mac_abort( operation );
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+psa_status_t psa_mac_sign_setup( psa_mac_operation_t *operation,
+                                 mbedtls_svc_key_id_t key,
+                                 psa_algorithm_t alg )
+{
+    return( psa_mac_setup( operation, key, alg, 1 ) );
+}
+
+psa_status_t psa_mac_verify_setup( psa_mac_operation_t *operation,
+                                   mbedtls_svc_key_id_t key,
+                                   psa_algorithm_t alg )
+{
+    return( psa_mac_setup( operation, key, alg, 0 ) );
+}
+
+psa_status_t psa_mac_update( psa_mac_operation_t *operation,
+                             const uint8_t *input,
+                             size_t input_length )
+{
+    if( operation->id == 0 )
+        return( PSA_ERROR_BAD_STATE );
+
+    /* Don't require hash implementations to behave correctly on a
+     * zero-length input, which may have an invalid pointer. */
+    if( input_length == 0 )
+        return( PSA_SUCCESS );
+
+    psa_status_t status = psa_driver_wrapper_mac_update( operation,
+                                                         input, input_length );
+    if( status != PSA_SUCCESS )
+        psa_mac_abort( operation );
+
+    return( status );
+}
+
+psa_status_t psa_mac_sign_finish( psa_mac_operation_t *operation,
+                                  uint8_t *mac,
+                                  size_t mac_size,
+                                  size_t *mac_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t abort_status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    if( operation->id == 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( ! operation->is_sign )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    /* Sanity check. This will guarantee that mac_size != 0 (and so mac != NULL)
+     * once all the error checks are done. */
+    if( operation->mac_size == 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( mac_size < operation->mac_size )
+    {
+        status = PSA_ERROR_BUFFER_TOO_SMALL;
+        goto exit;
+    }
+
+    status = psa_driver_wrapper_mac_sign_finish( operation,
+                                                 mac, operation->mac_size,
+                                                 mac_length );
+
+exit:
+    /* In case of success, set the potential excess room in the output buffer
+     * to an invalid value, to avoid potentially leaking a longer MAC.
+     * In case of error, set the output length and content to a safe default,
+     * such that in case the caller misses an error check, the output would be
+     * an unachievable MAC.
+     */
+    if( status != PSA_SUCCESS )
+    {
+        *mac_length = mac_size;
+        operation->mac_size = 0;
+    }
+
+    if( mac_size > operation->mac_size )
+        memset( &mac[operation->mac_size], '!',
+                mac_size - operation->mac_size );
+
+    abort_status = psa_mac_abort( operation );
+
+    return( status == PSA_SUCCESS ? abort_status : status );
+}
+
+psa_status_t psa_mac_verify_finish( psa_mac_operation_t *operation,
+                                    const uint8_t *mac,
+                                    size_t mac_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t abort_status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    if( operation->id == 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( operation->is_sign )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( operation->mac_size != mac_length )
+    {
+        status = PSA_ERROR_INVALID_SIGNATURE;
+        goto exit;
+    }
+
+    status = psa_driver_wrapper_mac_verify_finish( operation,
+                                                   mac, mac_length );
+
+exit:
+    abort_status = psa_mac_abort( operation );
+
+    return( status == PSA_SUCCESS ? abort_status : status );
+}
+
+static psa_status_t psa_mac_compute_internal( mbedtls_svc_key_id_t key,
+                                              psa_algorithm_t alg,
+                                              const uint8_t *input,
+                                              size_t input_length,
+                                              uint8_t *mac,
+                                              size_t mac_size,
+                                              size_t *mac_length,
+                                              int is_sign )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+    uint8_t operation_mac_size = 0;
+
+    status = psa_get_and_lock_key_slot_with_policy(
+                 key, &slot,
+                 is_sign ? PSA_KEY_USAGE_SIGN_HASH : PSA_KEY_USAGE_VERIFY_HASH,
+                 alg );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    psa_key_attributes_t attributes = {
+        .core = slot->attr
+    };
+
+    status = psa_mac_finalize_alg_and_key_validation( alg, &attributes,
+                                                      &operation_mac_size );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    if( mac_size < operation_mac_size )
+    {
+        status = PSA_ERROR_BUFFER_TOO_SMALL;
+        goto exit;
+    }
+
+    status = psa_driver_wrapper_mac_compute(
+                 &attributes,
+                 slot->key.data, slot->key.bytes,
+                 alg,
+                 input, input_length,
+                 mac, operation_mac_size, mac_length );
+
+exit:
+    /* In case of success, set the potential excess room in the output buffer
+     * to an invalid value, to avoid potentially leaking a longer MAC.
+     * In case of error, set the output length and content to a safe default,
+     * such that in case the caller misses an error check, the output would be
+     * an unachievable MAC.
+     */
+    if( status != PSA_SUCCESS )
+    {
+        *mac_length = mac_size;
+        operation_mac_size = 0;
+    }
+    if( mac_size > operation_mac_size )
+        memset( &mac[operation_mac_size], '!', mac_size - operation_mac_size );
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+psa_status_t psa_mac_compute( mbedtls_svc_key_id_t key,
+                              psa_algorithm_t alg,
+                              const uint8_t *input,
+                              size_t input_length,
+                              uint8_t *mac,
+                              size_t mac_size,
+                              size_t *mac_length)
+{
+    return( psa_mac_compute_internal( key, alg,
+                                      input, input_length,
+                                      mac, mac_size, mac_length, 1 ) );
+}
+
+psa_status_t psa_mac_verify( mbedtls_svc_key_id_t key,
+                             psa_algorithm_t alg,
+                             const uint8_t *input,
+                             size_t input_length,
+                             const uint8_t *mac,
+                             size_t mac_length)
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    uint8_t actual_mac[PSA_MAC_MAX_SIZE];
+    size_t actual_mac_length;
+
+    status = psa_mac_compute_internal( key, alg,
+                                       input, input_length,
+                                       actual_mac, sizeof( actual_mac ),
+                                       &actual_mac_length, 0 );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    if( mac_length != actual_mac_length )
+    {
+        status = PSA_ERROR_INVALID_SIGNATURE;
+        goto exit;
+    }
+    if( mbedtls_psa_safer_memcmp( mac, actual_mac, actual_mac_length ) != 0 )
+    {
+        status = PSA_ERROR_INVALID_SIGNATURE;
+        goto exit;
+    }
+
+exit:
+    mbedtls_platform_zeroize( actual_mac, sizeof( actual_mac ) );
+
+    return ( status );
+}
+
+/****************************************************************/
+/* Asymmetric cryptography */
+/****************************************************************/
+
+static psa_status_t psa_sign_verify_check_alg( int input_is_message,
+                                               psa_algorithm_t alg )
+{
+    if( input_is_message )
+    {
+        if( ! PSA_ALG_IS_SIGN_MESSAGE( alg ) )
+            return( PSA_ERROR_INVALID_ARGUMENT );
+
+        if ( PSA_ALG_IS_HASH_AND_SIGN( alg ) )
+        {
+            if( ! PSA_ALG_IS_HASH( PSA_ALG_SIGN_GET_HASH( alg ) ) )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+        }
+    }
+    else
+    {
+        if( ! PSA_ALG_IS_HASH_AND_SIGN( alg ) )
+            return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+
+    return( PSA_SUCCESS );
+}
+
+static psa_status_t psa_sign_internal( mbedtls_svc_key_id_t key,
+                                       int input_is_message,
+                                       psa_algorithm_t alg,
+                                       const uint8_t * input,
+                                       size_t input_length,
+                                       uint8_t * signature,
+                                       size_t signature_size,
+                                       size_t * signature_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    *signature_length = 0;
+
+    status = psa_sign_verify_check_alg( input_is_message, alg );
+    if( status != PSA_SUCCESS )
+        return status;
+
+    /* Immediately reject a zero-length signature buffer. This guarantees
+     * that signature must be a valid pointer. (On the other hand, the input
+     * buffer can in principle be empty since it doesn't actually have
+     * to be a hash.) */
+    if( signature_size == 0 )
+        return( PSA_ERROR_BUFFER_TOO_SMALL );
+
+    status = psa_get_and_lock_key_slot_with_policy(
+                key, &slot,
+                input_is_message ? PSA_KEY_USAGE_SIGN_MESSAGE :
+                                   PSA_KEY_USAGE_SIGN_HASH,
+                alg );
+
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    if( ! PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
+    if( input_is_message )
+    {
+        status = psa_driver_wrapper_sign_message(
+            &attributes, slot->key.data, slot->key.bytes,
+            alg, input, input_length,
+            signature, signature_size, signature_length );
+    }
+    else
+    {
+
+        status = psa_driver_wrapper_sign_hash(
+            &attributes, slot->key.data, slot->key.bytes,
+            alg, input, input_length,
+            signature, signature_size, signature_length );
+    }
+
+
+exit:
+    /* Fill the unused part of the output buffer (the whole buffer on error,
+     * the trailing part on success) with something that isn't a valid signature
+     * (barring an attack on the signature and deliberately-crafted input),
+     * in case the caller doesn't check the return status properly. */
+    if( status == PSA_SUCCESS )
+        memset( signature + *signature_length, '!',
+                signature_size - *signature_length );
+    else
+        memset( signature, '!', signature_size );
+    /* If signature_size is 0 then we have nothing to do. We must not call
+     * memset because signature may be NULL in this case. */
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+static psa_status_t psa_verify_internal( mbedtls_svc_key_id_t key,
+                                         int input_is_message,
+                                         psa_algorithm_t alg,
+                                         const uint8_t * input,
+                                         size_t input_length,
+                                         const uint8_t * signature,
+                                         size_t signature_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    status = psa_sign_verify_check_alg( input_is_message, alg );
+    if( status != PSA_SUCCESS )
+        return status;
+
+    status = psa_get_and_lock_key_slot_with_policy(
+                key, &slot,
+                input_is_message ? PSA_KEY_USAGE_VERIFY_MESSAGE :
+                                   PSA_KEY_USAGE_VERIFY_HASH,
+                alg );
+
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
+    if( input_is_message )
+    {
+        status = psa_driver_wrapper_verify_message(
+            &attributes, slot->key.data, slot->key.bytes,
+            alg, input, input_length,
+            signature, signature_length );
+    }
+    else
+    {
+        status = psa_driver_wrapper_verify_hash(
+            &attributes, slot->key.data, slot->key.bytes,
+            alg, input, input_length,
+            signature, signature_length );
+    }
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+
+}
+
+psa_status_t psa_sign_message_builtin(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer,
+    size_t key_buffer_size,
+    psa_algorithm_t alg,
+    const uint8_t *input,
+    size_t input_length,
+    uint8_t *signature,
+    size_t signature_size,
+    size_t *signature_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    if ( PSA_ALG_IS_HASH_AND_SIGN( alg ) )
+    {
+        size_t hash_length;
+        uint8_t hash[PSA_HASH_MAX_SIZE];
+
+        status = psa_driver_wrapper_hash_compute(
+                    PSA_ALG_SIGN_GET_HASH( alg ),
+                    input, input_length,
+                    hash, sizeof( hash ), &hash_length );
+
+        if( status != PSA_SUCCESS )
+            return status;
+
+        return psa_driver_wrapper_sign_hash(
+                    attributes, key_buffer, key_buffer_size,
+                    alg, hash, hash_length,
+                    signature, signature_size, signature_length );
+    }
+
+    return( PSA_ERROR_NOT_SUPPORTED );
+}
+
+psa_status_t psa_sign_message( mbedtls_svc_key_id_t key,
+                               psa_algorithm_t alg,
+                               const uint8_t * input,
+                               size_t input_length,
+                               uint8_t * signature,
+                               size_t signature_size,
+                               size_t * signature_length )
+{
+    return psa_sign_internal(
+        key, 1, alg, input, input_length,
+        signature, signature_size, signature_length );
+}
+
+psa_status_t psa_verify_message_builtin(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer,
+    size_t key_buffer_size,
+    psa_algorithm_t alg,
+    const uint8_t *input,
+    size_t input_length,
+    const uint8_t *signature,
+    size_t signature_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    if ( PSA_ALG_IS_HASH_AND_SIGN( alg ) )
+    {
+        size_t hash_length;
+        uint8_t hash[PSA_HASH_MAX_SIZE];
+
+        status = psa_driver_wrapper_hash_compute(
+                    PSA_ALG_SIGN_GET_HASH( alg ),
+                    input, input_length,
+                    hash, sizeof( hash ), &hash_length );
+
+        if( status != PSA_SUCCESS )
+            return status;
+
+        return psa_driver_wrapper_verify_hash(
+                    attributes, key_buffer, key_buffer_size,
+                    alg, hash, hash_length,
+                    signature, signature_length );
+    }
+
+    return( PSA_ERROR_NOT_SUPPORTED );
+}
+
+psa_status_t psa_verify_message( mbedtls_svc_key_id_t key,
+                                 psa_algorithm_t alg,
+                                 const uint8_t * input,
+                                 size_t input_length,
+                                 const uint8_t * signature,
+                                 size_t signature_length )
+{
+    return psa_verify_internal(
+        key, 1, alg, input, input_length,
+        signature, signature_length );
+}
+
+psa_status_t psa_sign_hash_builtin(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
+    uint8_t *signature, size_t signature_size, size_t *signature_length )
+{
+    if( attributes->core.type == PSA_KEY_TYPE_RSA_KEY_PAIR )
+    {
+        if( PSA_ALG_IS_RSA_PKCS1V15_SIGN( alg ) ||
+            PSA_ALG_IS_RSA_PSS( alg) )
+        {
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS)
+            return( mbedtls_psa_rsa_sign_hash(
+                        attributes,
+                        key_buffer, key_buffer_size,
+                        alg, hash, hash_length,
+                        signature, signature_size, signature_length ) );
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) */
+        }
+        else
+        {
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        }
+    }
+    else
+    if( PSA_KEY_TYPE_IS_ECC( attributes->core.type ) )
+    {
+        if( PSA_ALG_IS_ECDSA( alg ) )
+        {
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
+            return( mbedtls_psa_ecdsa_sign_hash(
+                        attributes,
+                        key_buffer, key_buffer_size,
+                        alg, hash, hash_length,
+                        signature, signature_size, signature_length ) );
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */
+        }
+        else
+        {
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        }
+    }
+
+    (void)key_buffer;
+    (void)key_buffer_size;
+    (void)hash;
+    (void)hash_length;
+    (void)signature;
+    (void)signature_size;
+    (void)signature_length;
+
+    return( PSA_ERROR_NOT_SUPPORTED );
+}
+
+psa_status_t psa_sign_hash( mbedtls_svc_key_id_t key,
+                            psa_algorithm_t alg,
+                            const uint8_t *hash,
+                            size_t hash_length,
+                            uint8_t *signature,
+                            size_t signature_size,
+                            size_t *signature_length )
+{
+    return psa_sign_internal(
+        key, 0, alg, hash, hash_length,
+        signature, signature_size, signature_length );
+}
+
+psa_status_t psa_verify_hash_builtin(
+    const psa_key_attributes_t *attributes,
+    const uint8_t *key_buffer, size_t key_buffer_size,
+    psa_algorithm_t alg, const uint8_t *hash, size_t hash_length,
+    const uint8_t *signature, size_t signature_length )
+{
+    if( PSA_KEY_TYPE_IS_RSA( attributes->core.type ) )
+    {
+        if( PSA_ALG_IS_RSA_PKCS1V15_SIGN( alg ) ||
+            PSA_ALG_IS_RSA_PSS( alg) )
+        {
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS)
+            return( mbedtls_psa_rsa_verify_hash(
+                        attributes,
+                        key_buffer, key_buffer_size,
+                        alg, hash, hash_length,
+                        signature, signature_length ) );
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) */
+        }
+        else
+        {
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        }
+    }
+    else
+    if( PSA_KEY_TYPE_IS_ECC( attributes->core.type ) )
+    {
+        if( PSA_ALG_IS_ECDSA( alg ) )
+        {
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
+            return( mbedtls_psa_ecdsa_verify_hash(
+                        attributes,
+                        key_buffer, key_buffer_size,
+                        alg, hash, hash_length,
+                        signature, signature_length ) );
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA) */
+        }
+        else
+        {
+            return( PSA_ERROR_INVALID_ARGUMENT );
+        }
+    }
+
+    (void)key_buffer;
+    (void)key_buffer_size;
+    (void)hash;
+    (void)hash_length;
+    (void)signature;
+    (void)signature_length;
+
+    return( PSA_ERROR_NOT_SUPPORTED );
+}
+
+psa_status_t psa_verify_hash( mbedtls_svc_key_id_t key,
+                              psa_algorithm_t alg,
+                              const uint8_t *hash,
+                              size_t hash_length,
+                              const uint8_t *signature,
+                              size_t signature_length )
+{
+    return psa_verify_internal(
+        key, 0, alg, hash, hash_length,
+        signature, signature_length );
+}
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP)
+static void psa_rsa_oaep_set_padding_mode( psa_algorithm_t alg,
+                                           mbedtls_rsa_context *rsa )
+{
+    psa_algorithm_t hash_alg = PSA_ALG_RSA_OAEP_GET_HASH( alg );
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_psa( hash_alg );
+    mbedtls_md_type_t md_alg = mbedtls_md_get_type( md_info );
+    mbedtls_rsa_set_padding( rsa, MBEDTLS_RSA_PKCS_V21, md_alg );
+}
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP) */
+
+psa_status_t psa_asymmetric_encrypt( mbedtls_svc_key_id_t key,
+                                     psa_algorithm_t alg,
+                                     const uint8_t *input,
+                                     size_t input_length,
+                                     const uint8_t *salt,
+                                     size_t salt_length,
+                                     uint8_t *output,
+                                     size_t output_size,
+                                     size_t *output_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    (void) input;
+    (void) input_length;
+    (void) salt;
+    (void) output;
+    (void) output_size;
+
+    *output_length = 0;
+
+    if( ! PSA_ALG_IS_RSA_OAEP( alg ) && salt_length != 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    status = psa_get_and_lock_transparent_key_slot_with_policy(
+                 key, &slot, PSA_KEY_USAGE_ENCRYPT, alg );
+    if( status != PSA_SUCCESS )
+        return( status );
+    if( ! ( PSA_KEY_TYPE_IS_PUBLIC_KEY( slot->attr.type ) ||
+            PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) ) )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP)
+    if( PSA_KEY_TYPE_IS_RSA( slot->attr.type ) )
+    {
+        mbedtls_rsa_context *rsa = NULL;
+        status = mbedtls_psa_rsa_load_representation( slot->attr.type,
+                                                      slot->key.data,
+                                                      slot->key.bytes,
+                                                      &rsa );
+        if( status != PSA_SUCCESS )
+            goto rsa_exit;
+
+        if( output_size < mbedtls_rsa_get_len( rsa ) )
+        {
+            status = PSA_ERROR_BUFFER_TOO_SMALL;
+            goto rsa_exit;
+        }
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT)
+        if( alg == PSA_ALG_RSA_PKCS1V15_CRYPT )
+        {
+            status = mbedtls_to_psa_error(
+                    mbedtls_rsa_pkcs1_encrypt( rsa,
+                                               mbedtls_psa_get_random,
+                                               MBEDTLS_PSA_RANDOM_STATE,
+                                               MBEDTLS_RSA_PUBLIC,
+                                               input_length,
+                                               input,
+                                               output ) );
+        }
+        else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP)
+        if( PSA_ALG_IS_RSA_OAEP( alg ) )
+        {
+            psa_rsa_oaep_set_padding_mode( alg, rsa );
+            status = mbedtls_to_psa_error(
+                mbedtls_rsa_rsaes_oaep_encrypt( rsa,
+                                                mbedtls_psa_get_random,
+                                                MBEDTLS_PSA_RANDOM_STATE,
+                                                MBEDTLS_RSA_PUBLIC,
+                                                salt, salt_length,
+                                                input_length,
+                                                input,
+                                                output ) );
+        }
+        else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP */
+        {
+            status = PSA_ERROR_INVALID_ARGUMENT;
+            goto rsa_exit;
+        }
+rsa_exit:
+        if( status == PSA_SUCCESS )
+            *output_length = mbedtls_rsa_get_len( rsa );
+
+        mbedtls_rsa_free( rsa );
+        mbedtls_free( rsa );
+    }
+    else
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP) */
+    {
+        status = PSA_ERROR_NOT_SUPPORTED;
+    }
+
+exit:
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+psa_status_t psa_asymmetric_decrypt( mbedtls_svc_key_id_t key,
+                                     psa_algorithm_t alg,
+                                     const uint8_t *input,
+                                     size_t input_length,
+                                     const uint8_t *salt,
+                                     size_t salt_length,
+                                     uint8_t *output,
+                                     size_t output_size,
+                                     size_t *output_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    (void) input;
+    (void) input_length;
+    (void) salt;
+    (void) output;
+    (void) output_size;
+
+    *output_length = 0;
+
+    if( ! PSA_ALG_IS_RSA_OAEP( alg ) && salt_length != 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    status = psa_get_and_lock_transparent_key_slot_with_policy(
+                 key, &slot, PSA_KEY_USAGE_DECRYPT, alg );
+    if( status != PSA_SUCCESS )
+        return( status );
+    if( ! PSA_KEY_TYPE_IS_KEY_PAIR( slot->attr.type ) )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP)
+    if( slot->attr.type == PSA_KEY_TYPE_RSA_KEY_PAIR )
+    {
+        mbedtls_rsa_context *rsa = NULL;
+        status = mbedtls_psa_rsa_load_representation( slot->attr.type,
+                                                      slot->key.data,
+                                                      slot->key.bytes,
+                                                      &rsa );
+        if( status != PSA_SUCCESS )
+            goto exit;
+
+        if( input_length != mbedtls_rsa_get_len( rsa ) )
+        {
+            status = PSA_ERROR_INVALID_ARGUMENT;
+            goto rsa_exit;
+        }
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT)
+        if( alg == PSA_ALG_RSA_PKCS1V15_CRYPT )
+        {
+            status = mbedtls_to_psa_error(
+                mbedtls_rsa_pkcs1_decrypt( rsa,
+                                           mbedtls_psa_get_random,
+                                           MBEDTLS_PSA_RANDOM_STATE,
+                                           MBEDTLS_RSA_PRIVATE,
+                                           output_length,
+                                           input,
+                                           output,
+                                           output_size ) );
+        }
+        else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP)
+        if( PSA_ALG_IS_RSA_OAEP( alg ) )
+        {
+            psa_rsa_oaep_set_padding_mode( alg, rsa );
+            status = mbedtls_to_psa_error(
+                mbedtls_rsa_rsaes_oaep_decrypt( rsa,
+                                                mbedtls_psa_get_random,
+                                                MBEDTLS_PSA_RANDOM_STATE,
+                                                MBEDTLS_RSA_PRIVATE,
+                                                salt, salt_length,
+                                                output_length,
+                                                input,
+                                                output,
+                                                output_size ) );
+        }
+        else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP */
+        {
+            status = PSA_ERROR_INVALID_ARGUMENT;
+        }
+
+rsa_exit:
+        mbedtls_rsa_free( rsa );
+        mbedtls_free( rsa );
+    }
+    else
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP) */
+    {
+        status = PSA_ERROR_NOT_SUPPORTED;
+    }
+
+exit:
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+
+
+/****************************************************************/
+/* Symmetric cryptography */
+/****************************************************************/
+
+static psa_status_t psa_cipher_setup( psa_cipher_operation_t *operation,
+                                      mbedtls_svc_key_id_t key,
+                                      psa_algorithm_t alg,
+                                      mbedtls_operation_t cipher_operation )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot = NULL;
+    psa_key_usage_t usage = ( cipher_operation == MBEDTLS_ENCRYPT ?
+                              PSA_KEY_USAGE_ENCRYPT :
+                              PSA_KEY_USAGE_DECRYPT );
+
+    /* A context must be freshly initialized before it can be set up. */
+    if( operation->id != 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( ! PSA_ALG_IS_CIPHER( alg ) )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+    status = psa_get_and_lock_key_slot_with_policy( key, &slot, usage, alg );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    /* Initialize the operation struct members, except for id. The id member
+     * is used to indicate to psa_cipher_abort that there are resources to free,
+     * so we only set it (in the driver wrapper) after resources have been
+     * allocated/initialized. */
+    operation->iv_set = 0;
+    if( alg == PSA_ALG_ECB_NO_PADDING )
+        operation->iv_required = 0;
+    else
+        operation->iv_required = 1;
+    operation->default_iv_length = PSA_CIPHER_IV_LENGTH( slot->attr.type, alg );
+
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
+    /* Try doing the operation through a driver before using software fallback. */
+    if( cipher_operation == MBEDTLS_ENCRYPT )
+        status = psa_driver_wrapper_cipher_encrypt_setup( operation,
+                                                          &attributes,
+                                                          slot->key.data,
+                                                          slot->key.bytes,
+                                                          alg );
+    else
+        status = psa_driver_wrapper_cipher_decrypt_setup( operation,
+                                                          &attributes,
+                                                          slot->key.data,
+                                                          slot->key.bytes,
+                                                          alg );
+
+exit:
+    if( status != PSA_SUCCESS )
+        psa_cipher_abort( operation );
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+psa_status_t psa_cipher_encrypt_setup( psa_cipher_operation_t *operation,
+                                       mbedtls_svc_key_id_t key,
+                                       psa_algorithm_t alg )
+{
+    return( psa_cipher_setup( operation, key, alg, MBEDTLS_ENCRYPT ) );
+}
+
+psa_status_t psa_cipher_decrypt_setup( psa_cipher_operation_t *operation,
+                                       mbedtls_svc_key_id_t key,
+                                       psa_algorithm_t alg )
+{
+    return( psa_cipher_setup( operation, key, alg, MBEDTLS_DECRYPT ) );
+}
+
+psa_status_t psa_cipher_generate_iv( psa_cipher_operation_t *operation,
+                                     uint8_t *iv,
+                                     size_t iv_size,
+                                     size_t *iv_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    *iv_length = 0;
+
+    if( operation->id == 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( operation->iv_set || ! operation->iv_required )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( iv_size < operation->default_iv_length )
+    {
+        status = PSA_ERROR_BUFFER_TOO_SMALL;
+        goto exit;
+    }
+
+    status = psa_generate_random( iv, operation->default_iv_length );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_driver_wrapper_cipher_set_iv( operation,
+                                               iv,
+                                               operation->default_iv_length );
+
+exit:
+    if( status == PSA_SUCCESS )
+    {
+        operation->iv_set = 1;
+        *iv_length = operation->default_iv_length;
+    }
+    else
+        psa_cipher_abort( operation );
+
+    return( status );
+}
+
+psa_status_t psa_cipher_set_iv( psa_cipher_operation_t *operation,
+                                const uint8_t *iv,
+                                size_t iv_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    if( operation->id == 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( operation->iv_set || ! operation->iv_required )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( iv_length > PSA_CIPHER_IV_MAX_SIZE )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+    status = psa_driver_wrapper_cipher_set_iv( operation,
+                                               iv,
+                                               iv_length );
+
+exit:
+    if( status == PSA_SUCCESS )
+        operation->iv_set = 1;
+    else
+        psa_cipher_abort( operation );
+    return( status );
+}
+
+psa_status_t psa_cipher_update( psa_cipher_operation_t *operation,
+                                const uint8_t *input,
+                                size_t input_length,
+                                uint8_t *output,
+                                size_t output_size,
+                                size_t *output_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    if( operation->id == 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( operation->iv_required && ! operation->iv_set )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    status = psa_driver_wrapper_cipher_update( operation,
+                                               input,
+                                               input_length,
+                                               output,
+                                               output_size,
+                                               output_length );
+
+exit:
+    if( status != PSA_SUCCESS )
+        psa_cipher_abort( operation );
+
+    return( status );
+}
+
+psa_status_t psa_cipher_finish( psa_cipher_operation_t *operation,
+                                uint8_t *output,
+                                size_t output_size,
+                                size_t *output_length )
+{
+    psa_status_t status = PSA_ERROR_GENERIC_ERROR;
+
+    if( operation->id == 0 )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    if( operation->iv_required && ! operation->iv_set )
+    {
+        status = PSA_ERROR_BAD_STATE;
+        goto exit;
+    }
+
+    status = psa_driver_wrapper_cipher_finish( operation,
+                                               output,
+                                               output_size,
+                                               output_length );
+
+exit:
+    if( status == PSA_SUCCESS )
+        return( psa_cipher_abort( operation ) );
+    else
+    {
+        *output_length = 0;
+        (void) psa_cipher_abort( operation );
+
+        return( status );
+    }
+}
+
+psa_status_t psa_cipher_abort( psa_cipher_operation_t *operation )
+{
+    if( operation->id == 0 )
+    {
+        /* The object has (apparently) been initialized but it is not (yet)
+         * in use. It's ok to call abort on such an object, and there's
+         * nothing to do. */
+        return( PSA_SUCCESS );
+    }
+
+    psa_driver_wrapper_cipher_abort( operation );
+
+    operation->id = 0;
+    operation->iv_set = 0;
+    operation->iv_required = 0;
+
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_cipher_encrypt( mbedtls_svc_key_id_t key,
+                                 psa_algorithm_t alg,
+                                 const uint8_t *input,
+                                 size_t input_length,
+                                 uint8_t *output,
+                                 size_t output_size,
+                                 size_t *output_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+    psa_key_type_t key_type;
+    size_t iv_length;
+
+    *output_length = 0;
+
+    if( ! PSA_ALG_IS_CIPHER( alg ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    status = psa_get_and_lock_key_slot_with_policy( key, &slot,
+                                                    PSA_KEY_USAGE_ENCRYPT,
+                                                    alg );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
+    key_type = slot->attr.type;
+    iv_length = PSA_CIPHER_IV_LENGTH( key_type, alg );
+
+    if( iv_length > 0 )
+    {
+        if( output_size < iv_length )
+        {
+            status = PSA_ERROR_BUFFER_TOO_SMALL;
+            goto exit;
+        }
+
+        status = psa_generate_random( output, iv_length );
+        if( status != PSA_SUCCESS )
+            goto exit;
+    }
+
+    status = psa_driver_wrapper_cipher_encrypt(
+        &attributes, slot->key.data, slot->key.bytes,
+        alg, input, input_length,
+        output, output_size, output_length );
+
+exit:
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+psa_status_t psa_cipher_decrypt( mbedtls_svc_key_id_t key,
+                                 psa_algorithm_t alg,
+                                 const uint8_t *input,
+                                 size_t input_length,
+                                 uint8_t *output,
+                                 size_t output_size,
+                                 size_t *output_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    *output_length = 0;
+
+    if( ! PSA_ALG_IS_CIPHER( alg ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    status = psa_get_and_lock_key_slot_with_policy( key, &slot,
+                                                    PSA_KEY_USAGE_DECRYPT,
+                                                    alg );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
+    if( input_length < PSA_CIPHER_IV_LENGTH( slot->attr.type, alg ) )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+    status = psa_driver_wrapper_cipher_decrypt(
+        &attributes, slot->key.data, slot->key.bytes,
+        alg, input, input_length,
+        output, output_size, output_length );
+
+exit:
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+
+/****************************************************************/
+/* AEAD */
+/****************************************************************/
+
+psa_status_t psa_aead_encrypt( mbedtls_svc_key_id_t key,
+                               psa_algorithm_t alg,
+                               const uint8_t *nonce,
+                               size_t nonce_length,
+                               const uint8_t *additional_data,
+                               size_t additional_data_length,
+                               const uint8_t *plaintext,
+                               size_t plaintext_length,
+                               uint8_t *ciphertext,
+                               size_t ciphertext_size,
+                               size_t *ciphertext_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    *ciphertext_length = 0;
+
+    if( !PSA_ALG_IS_AEAD( alg ) || PSA_ALG_IS_WILDCARD( alg ) )
+        return( PSA_ERROR_NOT_SUPPORTED );
+
+    status = psa_get_and_lock_key_slot_with_policy(
+                 key, &slot, PSA_KEY_USAGE_ENCRYPT, alg );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
+    status = psa_driver_wrapper_aead_encrypt(
+        &attributes, slot->key.data, slot->key.bytes,
+        alg,
+        nonce, nonce_length,
+        additional_data, additional_data_length,
+        plaintext, plaintext_length,
+        ciphertext, ciphertext_size, ciphertext_length );
+
+    if( status != PSA_SUCCESS && ciphertext_size != 0 )
+        memset( ciphertext, 0, ciphertext_size );
+
+    psa_unlock_key_slot( slot );
+
+    return( status );
+}
+
+psa_status_t psa_aead_decrypt( mbedtls_svc_key_id_t key,
+                               psa_algorithm_t alg,
+                               const uint8_t *nonce,
+                               size_t nonce_length,
+                               const uint8_t *additional_data,
+                               size_t additional_data_length,
+                               const uint8_t *ciphertext,
+                               size_t ciphertext_length,
+                               uint8_t *plaintext,
+                               size_t plaintext_size,
+                               size_t *plaintext_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    *plaintext_length = 0;
+
+    if( !PSA_ALG_IS_AEAD( alg ) || PSA_ALG_IS_WILDCARD( alg ) )
+        return( PSA_ERROR_NOT_SUPPORTED );
+
+    status = psa_get_and_lock_key_slot_with_policy(
+                 key, &slot, PSA_KEY_USAGE_DECRYPT, alg );
+    if( status != PSA_SUCCESS )
+        return( status );
+
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
+    status = psa_driver_wrapper_aead_decrypt(
+        &attributes, slot->key.data, slot->key.bytes,
+        alg,
+        nonce, nonce_length,
+        additional_data, additional_data_length,
+        ciphertext, ciphertext_length,
+        plaintext, plaintext_size, plaintext_length );
+
+    if( status != PSA_SUCCESS && plaintext_size != 0 )
+        memset( plaintext, 0, plaintext_size );
+
+    psa_unlock_key_slot( slot );
+
+    return( status );
+}
+
+/****************************************************************/
+/* Generators */
+/****************************************************************/
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+#define AT_LEAST_ONE_BUILTIN_KDF
+#endif /* At least one builtin KDF */
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+static psa_status_t psa_key_derivation_start_hmac(
+    psa_mac_operation_t *operation,
+    psa_algorithm_t hash_alg,
+    const uint8_t *hmac_key,
+    size_t hmac_key_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
+    psa_set_key_type( &attributes, PSA_KEY_TYPE_HMAC );
+    psa_set_key_bits( &attributes, PSA_BYTES_TO_BITS( hmac_key_length ) );
+    psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_SIGN_HASH );
+
+    operation->is_sign = 1;
+    operation->mac_size = PSA_HASH_LENGTH( hash_alg );
+
+    status = psa_driver_wrapper_mac_sign_setup( operation,
+                                                &attributes,
+                                                hmac_key, hmac_key_length,
+                                                PSA_ALG_HMAC( hash_alg ) );
+
+    psa_reset_key_attributes( &attributes );
+    return( status );
+}
+#endif /* KDF algorithms reliant on HMAC */
+
+#define HKDF_STATE_INIT 0 /* no input yet */
+#define HKDF_STATE_STARTED 1 /* got salt */
+#define HKDF_STATE_KEYED 2 /* got key */
+#define HKDF_STATE_OUTPUT 3 /* output started */
+
+static psa_algorithm_t psa_key_derivation_get_kdf_alg(
+    const psa_key_derivation_operation_t *operation )
+{
+    if ( PSA_ALG_IS_KEY_AGREEMENT( operation->alg ) )
+        return( PSA_ALG_KEY_AGREEMENT_GET_KDF( operation->alg ) );
+    else
+        return( operation->alg );
+}
+
+psa_status_t psa_key_derivation_abort( psa_key_derivation_operation_t *operation )
+{
+    psa_status_t status = PSA_SUCCESS;
+    psa_algorithm_t kdf_alg = psa_key_derivation_get_kdf_alg( operation );
+    if( kdf_alg == 0 )
+    {
+        /* The object has (apparently) been initialized but it is not
+         * in use. It's ok to call abort on such an object, and there's
+         * nothing to do. */
+    }
+    else
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
+    if( PSA_ALG_IS_HKDF( kdf_alg ) )
+    {
+        mbedtls_free( operation->ctx.hkdf.info );
+        status = psa_mac_abort( &operation->ctx.hkdf.hmac );
+    }
+    else
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+    if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) ||
+             /* TLS-1.2 PSK-to-MS KDF uses the same core as TLS-1.2 PRF */
+             PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) )
+    {
+        if( operation->ctx.tls12_prf.secret != NULL )
+        {
+            mbedtls_platform_zeroize( operation->ctx.tls12_prf.secret,
+                                      operation->ctx.tls12_prf.secret_length );
+            mbedtls_free( operation->ctx.tls12_prf.secret );
+        }
+
+        if( operation->ctx.tls12_prf.seed != NULL )
+        {
+            mbedtls_platform_zeroize( operation->ctx.tls12_prf.seed,
+                                      operation->ctx.tls12_prf.seed_length );
+            mbedtls_free( operation->ctx.tls12_prf.seed );
+        }
+
+        if( operation->ctx.tls12_prf.label != NULL )
+        {
+            mbedtls_platform_zeroize( operation->ctx.tls12_prf.label,
+                                      operation->ctx.tls12_prf.label_length );
+            mbedtls_free( operation->ctx.tls12_prf.label );
+        }
+
+        status = PSA_SUCCESS;
+
+        /* We leave the fields Ai and output_block to be erased safely by the
+         * mbedtls_platform_zeroize() in the end of this function. */
+    }
+    else
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS) */
+    {
+        status = PSA_ERROR_BAD_STATE;
+    }
+    mbedtls_platform_zeroize( operation, sizeof( *operation ) );
+    return( status );
+}
+
+psa_status_t psa_key_derivation_get_capacity(const psa_key_derivation_operation_t *operation,
+                                        size_t *capacity)
+{
+    if( operation->alg == 0 )
+    {
+        /* This is a blank key derivation operation. */
+        return( PSA_ERROR_BAD_STATE );
+    }
+
+    *capacity = operation->capacity;
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_key_derivation_set_capacity( psa_key_derivation_operation_t *operation,
+                                         size_t capacity )
+{
+    if( operation->alg == 0 )
+        return( PSA_ERROR_BAD_STATE );
+    if( capacity > operation->capacity )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    operation->capacity = capacity;
+    return( PSA_SUCCESS );
+}
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
+/* Read some bytes from an HKDF-based operation. This performs a chunk
+ * of the expand phase of the HKDF algorithm. */
+static psa_status_t psa_key_derivation_hkdf_read( psa_hkdf_key_derivation_t *hkdf,
+                                                  psa_algorithm_t hash_alg,
+                                                  uint8_t *output,
+                                                  size_t output_length )
+{
+    uint8_t hash_length = PSA_HASH_LENGTH( hash_alg );
+    size_t hmac_output_length;
+    psa_status_t status;
+
+    if( hkdf->state < HKDF_STATE_KEYED || ! hkdf->info_set )
+        return( PSA_ERROR_BAD_STATE );
+    hkdf->state = HKDF_STATE_OUTPUT;
+
+    while( output_length != 0 )
+    {
+        /* Copy what remains of the current block */
+        uint8_t n = hash_length - hkdf->offset_in_block;
+        if( n > output_length )
+            n = (uint8_t) output_length;
+        memcpy( output, hkdf->output_block + hkdf->offset_in_block, n );
+        output += n;
+        output_length -= n;
+        hkdf->offset_in_block += n;
+        if( output_length == 0 )
+            break;
+        /* We can't be wanting more output after block 0xff, otherwise
+         * the capacity check in psa_key_derivation_output_bytes() would have
+         * prevented this call. It could happen only if the operation
+         * object was corrupted or if this function is called directly
+         * inside the library. */
+        if( hkdf->block_number == 0xff )
+            return( PSA_ERROR_BAD_STATE );
+
+        /* We need a new block */
+        ++hkdf->block_number;
+        hkdf->offset_in_block = 0;
+
+        status = psa_key_derivation_start_hmac( &hkdf->hmac,
+                                                hash_alg,
+                                                hkdf->prk,
+                                                hash_length );
+        if( status != PSA_SUCCESS )
+            return( status );
+
+        if( hkdf->block_number != 1 )
+        {
+            status = psa_mac_update( &hkdf->hmac,
+                                     hkdf->output_block,
+                                     hash_length );
+            if( status != PSA_SUCCESS )
+                return( status );
+        }
+        status = psa_mac_update( &hkdf->hmac,
+                                 hkdf->info,
+                                 hkdf->info_length );
+        if( status != PSA_SUCCESS )
+            return( status );
+        status = psa_mac_update( &hkdf->hmac,
+                                 &hkdf->block_number, 1 );
+        if( status != PSA_SUCCESS )
+            return( status );
+        status = psa_mac_sign_finish( &hkdf->hmac,
+                                      hkdf->output_block,
+                                      sizeof( hkdf->output_block ),
+                                      &hmac_output_length );
+        if( status != PSA_SUCCESS )
+            return( status );
+    }
+
+    return( PSA_SUCCESS );
+}
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF */
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+static psa_status_t psa_key_derivation_tls12_prf_generate_next_block(
+    psa_tls12_prf_key_derivation_t *tls12_prf,
+    psa_algorithm_t alg )
+{
+    psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( alg );
+    uint8_t hash_length = PSA_HASH_LENGTH( hash_alg );
+    psa_mac_operation_t hmac = PSA_MAC_OPERATION_INIT;
+    size_t hmac_output_length;
+    psa_status_t status, cleanup_status;
+
+    /* We can't be wanting more output after block 0xff, otherwise
+     * the capacity check in psa_key_derivation_output_bytes() would have
+     * prevented this call. It could happen only if the operation
+     * object was corrupted or if this function is called directly
+     * inside the library. */
+    if( tls12_prf->block_number == 0xff )
+        return( PSA_ERROR_CORRUPTION_DETECTED );
+
+    /* We need a new block */
+    ++tls12_prf->block_number;
+    tls12_prf->left_in_block = hash_length;
+
+    /* Recall the definition of the TLS-1.2-PRF from RFC 5246:
+     *
+     * PRF(secret, label, seed) = P_<hash>(secret, label + seed)
+     *
+     * P_hash(secret, seed) = HMAC_hash(secret, A(1) + seed) +
+     *                        HMAC_hash(secret, A(2) + seed) +
+     *                        HMAC_hash(secret, A(3) + seed) + ...
+     *
+     * A(0) = seed
+     * A(i) = HMAC_hash(secret, A(i-1))
+     *
+     * The `psa_tls12_prf_key_derivation` structure saves the block
+     * `HMAC_hash(secret, A(i) + seed)` from which the output
+     * is currently extracted as `output_block` and where i is
+     * `block_number`.
+     */
+
+    status = psa_key_derivation_start_hmac( &hmac,
+                                            hash_alg,
+                                            tls12_prf->secret,
+                                            tls12_prf->secret_length );
+    if( status != PSA_SUCCESS )
+        goto cleanup;
+
+    /* Calculate A(i) where i = tls12_prf->block_number. */
+    if( tls12_prf->block_number == 1 )
+    {
+        /* A(1) = HMAC_hash(secret, A(0)), where A(0) = seed. (The RFC overloads
+         * the variable seed and in this instance means it in the context of the
+         * P_hash function, where seed = label + seed.) */
+        status = psa_mac_update( &hmac,
+                                 tls12_prf->label,
+                                 tls12_prf->label_length );
+        if( status != PSA_SUCCESS )
+            goto cleanup;
+        status = psa_mac_update( &hmac,
+                                 tls12_prf->seed,
+                                 tls12_prf->seed_length );
+        if( status != PSA_SUCCESS )
+            goto cleanup;
+    }
+    else
+    {
+        /* A(i) = HMAC_hash(secret, A(i-1)) */
+        status = psa_mac_update( &hmac, tls12_prf->Ai, hash_length );
+        if( status != PSA_SUCCESS )
+            goto cleanup;
+    }
+
+    status = psa_mac_sign_finish( &hmac,
+                                  tls12_prf->Ai, hash_length,
+                                  &hmac_output_length );
+    if( hmac_output_length != hash_length )
+        status = PSA_ERROR_CORRUPTION_DETECTED;
+    if( status != PSA_SUCCESS )
+        goto cleanup;
+
+    /* Calculate HMAC_hash(secret, A(i) + label + seed). */
+    status = psa_key_derivation_start_hmac( &hmac,
+                                            hash_alg,
+                                            tls12_prf->secret,
+                                            tls12_prf->secret_length );
+    if( status != PSA_SUCCESS )
+        goto cleanup;
+    status = psa_mac_update( &hmac, tls12_prf->Ai, hash_length );
+    if( status != PSA_SUCCESS )
+        goto cleanup;
+    status = psa_mac_update( &hmac, tls12_prf->label, tls12_prf->label_length );
+    if( status != PSA_SUCCESS )
+        goto cleanup;
+    status = psa_mac_update( &hmac, tls12_prf->seed, tls12_prf->seed_length );
+    if( status != PSA_SUCCESS )
+        goto cleanup;
+    status = psa_mac_sign_finish( &hmac,
+                                  tls12_prf->output_block, hash_length,
+                                  &hmac_output_length );
+    if( status != PSA_SUCCESS )
+        goto cleanup;
+
+
+cleanup:
+    cleanup_status = psa_mac_abort( &hmac );
+    if( status == PSA_SUCCESS && cleanup_status != PSA_SUCCESS )
+        status = cleanup_status;
+
+    return( status );
+}
+
+static psa_status_t psa_key_derivation_tls12_prf_read(
+    psa_tls12_prf_key_derivation_t *tls12_prf,
+    psa_algorithm_t alg,
+    uint8_t *output,
+    size_t output_length )
+{
+    psa_algorithm_t hash_alg = PSA_ALG_TLS12_PRF_GET_HASH( alg );
+    uint8_t hash_length = PSA_HASH_LENGTH( hash_alg );
+    psa_status_t status;
+    uint8_t offset, length;
+
+    switch( tls12_prf->state )
+    {
+        case PSA_TLS12_PRF_STATE_LABEL_SET:
+            tls12_prf->state = PSA_TLS12_PRF_STATE_OUTPUT;
+            break;
+        case PSA_TLS12_PRF_STATE_OUTPUT:
+            break;
+        default:
+            return( PSA_ERROR_BAD_STATE );
+    }
+
+    while( output_length != 0 )
+    {
+        /* Check if we have fully processed the current block. */
+        if( tls12_prf->left_in_block == 0 )
+        {
+            status = psa_key_derivation_tls12_prf_generate_next_block( tls12_prf,
+                                                                       alg );
+            if( status != PSA_SUCCESS )
+                return( status );
+
+            continue;
+        }
+
+        if( tls12_prf->left_in_block > output_length )
+            length = (uint8_t) output_length;
+        else
+            length = tls12_prf->left_in_block;
+
+        offset = hash_length - tls12_prf->left_in_block;
+        memcpy( output, tls12_prf->output_block + offset, length );
+        output += length;
+        output_length -= length;
+        tls12_prf->left_in_block -= length;
+    }
+
+    return( PSA_SUCCESS );
+}
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF ||
+        * MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */
+
+psa_status_t psa_key_derivation_output_bytes(
+    psa_key_derivation_operation_t *operation,
+    uint8_t *output,
+    size_t output_length )
+{
+    psa_status_t status;
+    psa_algorithm_t kdf_alg = psa_key_derivation_get_kdf_alg( operation );
+
+    if( operation->alg == 0 )
+    {
+        /* This is a blank operation. */
+        return( PSA_ERROR_BAD_STATE );
+    }
+
+    if( output_length > operation->capacity )
+    {
+        operation->capacity = 0;
+        /* Go through the error path to wipe all confidential data now
+         * that the operation object is useless. */
+        status = PSA_ERROR_INSUFFICIENT_DATA;
+        goto exit;
+    }
+    if( output_length == 0 && operation->capacity == 0 )
+    {
+        /* Edge case: this is a finished operation, and 0 bytes
+         * were requested. The right error in this case could
+         * be either INSUFFICIENT_CAPACITY or BAD_STATE. Return
+         * INSUFFICIENT_CAPACITY, which is right for a finished
+         * operation, for consistency with the case when
+         * output_length > 0. */
+        return( PSA_ERROR_INSUFFICIENT_DATA );
+    }
+    operation->capacity -= output_length;
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
+    if( PSA_ALG_IS_HKDF( kdf_alg ) )
+    {
+        psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( kdf_alg );
+        status = psa_key_derivation_hkdf_read( &operation->ctx.hkdf, hash_alg,
+                                          output, output_length );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+    if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) ||
+        PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) )
+    {
+        status = psa_key_derivation_tls12_prf_read( &operation->ctx.tls12_prf,
+                                                    kdf_alg, output,
+                                                    output_length );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF ||
+        * MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */
+    {
+        (void) kdf_alg;
+        return( PSA_ERROR_BAD_STATE );
+    }
+
+exit:
+    if( status != PSA_SUCCESS )
+    {
+        /* Preserve the algorithm upon errors, but clear all sensitive state.
+         * This allows us to differentiate between exhausted operations and
+         * blank operations, so we can return PSA_ERROR_BAD_STATE on blank
+         * operations. */
+        psa_algorithm_t alg = operation->alg;
+        psa_key_derivation_abort( operation );
+        operation->alg = alg;
+        memset( output, '!', output_length );
+    }
+    return( status );
+}
+
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES)
+static void psa_des_set_key_parity( uint8_t *data, size_t data_size )
+{
+    if( data_size >= 8 )
+        mbedtls_des_key_set_parity( data );
+    if( data_size >= 16 )
+        mbedtls_des_key_set_parity( data + 8 );
+    if( data_size >= 24 )
+        mbedtls_des_key_set_parity( data + 16 );
+}
+#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES */
+
+static psa_status_t psa_generate_derived_key_internal(
+    psa_key_slot_t *slot,
+    size_t bits,
+    psa_key_derivation_operation_t *operation )
+{
+    uint8_t *data = NULL;
+    size_t bytes = PSA_BITS_TO_BYTES( bits );
+    psa_status_t status;
+
+    if( ! key_type_is_raw_bytes( slot->attr.type ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    if( bits % 8 != 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    data = mbedtls_calloc( 1, bytes );
+    if( data == NULL )
+        return( PSA_ERROR_INSUFFICIENT_MEMORY );
+
+    status = psa_key_derivation_output_bytes( operation, data, bytes );
+    if( status != PSA_SUCCESS )
+        goto exit;
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES)
+    if( slot->attr.type == PSA_KEY_TYPE_DES )
+        psa_des_set_key_parity( data, bytes );
+#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES */
+
+    status = psa_allocate_buffer_to_slot( slot, bytes );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    slot->attr.bits = (psa_key_bits_t) bits;
+    psa_key_attributes_t attributes = {
+      .core = slot->attr
+    };
+
+    status = psa_driver_wrapper_import_key( &attributes,
+                                            data, bytes,
+                                            slot->key.data,
+                                            slot->key.bytes,
+                                            &slot->key.bytes, &bits );
+    if( bits != slot->attr.bits )
+        status = PSA_ERROR_INVALID_ARGUMENT;
+
+exit:
+    mbedtls_free( data );
+    return( status );
+}
+
+psa_status_t psa_key_derivation_output_key( const psa_key_attributes_t *attributes,
+                                       psa_key_derivation_operation_t *operation,
+                                       mbedtls_svc_key_id_t *key )
+{
+    psa_status_t status;
+    psa_key_slot_t *slot = NULL;
+    psa_se_drv_table_entry_t *driver = NULL;
+
+    *key = MBEDTLS_SVC_KEY_ID_INIT;
+
+    /* Reject any attempt to create a zero-length key so that we don't
+     * risk tripping up later, e.g. on a malloc(0) that returns NULL. */
+    if( psa_get_key_bits( attributes ) == 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    if( ! operation->can_output_key )
+        return( PSA_ERROR_NOT_PERMITTED );
+
+    status = psa_start_key_creation( PSA_KEY_CREATION_DERIVE, attributes,
+                                     &slot, &driver );
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    if( driver != NULL )
+    {
+        /* Deriving a key in a secure element is not implemented yet. */
+        status = PSA_ERROR_NOT_SUPPORTED;
+    }
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+    if( status == PSA_SUCCESS )
+    {
+        status = psa_generate_derived_key_internal( slot,
+                                                    attributes->core.bits,
+                                                    operation );
+    }
+    if( status == PSA_SUCCESS )
+        status = psa_finish_key_creation( slot, driver, key );
+    if( status != PSA_SUCCESS )
+        psa_fail_key_creation( slot, driver );
+
+    return( status );
+}
+
+
+
+/****************************************************************/
+/* Key derivation */
+/****************************************************************/
+
+#if defined(AT_LEAST_ONE_BUILTIN_KDF)
+static psa_status_t psa_key_derivation_setup_kdf(
+    psa_key_derivation_operation_t *operation,
+    psa_algorithm_t kdf_alg )
+{
+    int is_kdf_alg_supported;
+
+    /* Make sure that operation->ctx is properly zero-initialised. (Macro
+     * initialisers for this union leave some bytes unspecified.) */
+    memset( &operation->ctx, 0, sizeof( operation->ctx ) );
+
+    /* Make sure that kdf_alg is a supported key derivation algorithm. */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
+    if( PSA_ALG_IS_HKDF( kdf_alg ) )
+        is_kdf_alg_supported = 1;
+    else
+#endif
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF)
+    if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) )
+        is_kdf_alg_supported = 1;
+    else
+#endif
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+    if( PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) )
+        is_kdf_alg_supported = 1;
+    else
+#endif
+    is_kdf_alg_supported = 0;
+
+    if( is_kdf_alg_supported )
+    {
+        psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( kdf_alg );
+        size_t hash_size = PSA_HASH_LENGTH( hash_alg );
+        if( hash_size == 0 )
+            return( PSA_ERROR_NOT_SUPPORTED );
+        if( ( PSA_ALG_IS_TLS12_PRF( kdf_alg ) ||
+              PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) &&
+            ! ( hash_alg == PSA_ALG_SHA_256 || hash_alg == PSA_ALG_SHA_384 ) )
+        {
+            return( PSA_ERROR_NOT_SUPPORTED );
+        }
+        operation->capacity = 255 * hash_size;
+        return( PSA_SUCCESS );
+    }
+
+    return( PSA_ERROR_NOT_SUPPORTED );
+}
+#endif /* AT_LEAST_ONE_BUILTIN_KDF */
+
+psa_status_t psa_key_derivation_setup( psa_key_derivation_operation_t *operation,
+                                       psa_algorithm_t alg )
+{
+    psa_status_t status;
+
+    if( operation->alg != 0 )
+        return( PSA_ERROR_BAD_STATE );
+
+    if( PSA_ALG_IS_RAW_KEY_AGREEMENT( alg ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    else if( PSA_ALG_IS_KEY_AGREEMENT( alg ) )
+    {
+#if defined(AT_LEAST_ONE_BUILTIN_KDF)
+        psa_algorithm_t kdf_alg = PSA_ALG_KEY_AGREEMENT_GET_KDF( alg );
+        status = psa_key_derivation_setup_kdf( operation, kdf_alg );
+#else
+        return( PSA_ERROR_NOT_SUPPORTED );
+#endif /* AT_LEAST_ONE_BUILTIN_KDF */
+    }
+    else if( PSA_ALG_IS_KEY_DERIVATION( alg ) )
+    {
+#if defined(AT_LEAST_ONE_BUILTIN_KDF)
+        status = psa_key_derivation_setup_kdf( operation, alg );
+#else
+        return( PSA_ERROR_NOT_SUPPORTED );
+#endif /* AT_LEAST_ONE_BUILTIN_KDF */
+    }
+    else
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    if( status == PSA_SUCCESS )
+        operation->alg = alg;
+    return( status );
+}
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
+static psa_status_t psa_hkdf_input( psa_hkdf_key_derivation_t *hkdf,
+                                    psa_algorithm_t hash_alg,
+                                    psa_key_derivation_step_t step,
+                                    const uint8_t *data,
+                                    size_t data_length )
+{
+    psa_status_t status;
+    switch( step )
+    {
+        case PSA_KEY_DERIVATION_INPUT_SALT:
+            if( hkdf->state != HKDF_STATE_INIT )
+                return( PSA_ERROR_BAD_STATE );
+            else
+            {
+                status = psa_key_derivation_start_hmac( &hkdf->hmac,
+                                                        hash_alg,
+                                                        data, data_length );
+                if( status != PSA_SUCCESS )
+                    return( status );
+                hkdf->state = HKDF_STATE_STARTED;
+                return( PSA_SUCCESS );
+            }
+        case PSA_KEY_DERIVATION_INPUT_SECRET:
+            /* If no salt was provided, use an empty salt. */
+            if( hkdf->state == HKDF_STATE_INIT )
+            {
+                status = psa_key_derivation_start_hmac( &hkdf->hmac,
+                                                        hash_alg,
+                                                        NULL, 0 );
+                if( status != PSA_SUCCESS )
+                    return( status );
+                hkdf->state = HKDF_STATE_STARTED;
+            }
+            if( hkdf->state != HKDF_STATE_STARTED )
+                return( PSA_ERROR_BAD_STATE );
+            status = psa_mac_update( &hkdf->hmac,
+                                     data, data_length );
+            if( status != PSA_SUCCESS )
+                return( status );
+            status = psa_mac_sign_finish( &hkdf->hmac,
+                                          hkdf->prk,
+                                          sizeof( hkdf->prk ),
+                                          &data_length );
+            if( status != PSA_SUCCESS )
+                return( status );
+            hkdf->offset_in_block = PSA_HASH_LENGTH( hash_alg );
+            hkdf->block_number = 0;
+            hkdf->state = HKDF_STATE_KEYED;
+            return( PSA_SUCCESS );
+        case PSA_KEY_DERIVATION_INPUT_INFO:
+            if( hkdf->state == HKDF_STATE_OUTPUT )
+                return( PSA_ERROR_BAD_STATE );
+            if( hkdf->info_set )
+                return( PSA_ERROR_BAD_STATE );
+            hkdf->info_length = data_length;
+            if( data_length != 0 )
+            {
+                hkdf->info = mbedtls_calloc( 1, data_length );
+                if( hkdf->info == NULL )
+                    return( PSA_ERROR_INSUFFICIENT_MEMORY );
+                memcpy( hkdf->info, data, data_length );
+            }
+            hkdf->info_set = 1;
+            return( PSA_SUCCESS );
+        default:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+}
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF */
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+static psa_status_t psa_tls12_prf_set_seed( psa_tls12_prf_key_derivation_t *prf,
+                                            const uint8_t *data,
+                                            size_t data_length )
+{
+    if( prf->state != PSA_TLS12_PRF_STATE_INIT )
+        return( PSA_ERROR_BAD_STATE );
+
+    if( data_length != 0 )
+    {
+        prf->seed = mbedtls_calloc( 1, data_length );
+        if( prf->seed == NULL )
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+
+        memcpy( prf->seed, data, data_length );
+        prf->seed_length = data_length;
+    }
+
+    prf->state = PSA_TLS12_PRF_STATE_SEED_SET;
+
+    return( PSA_SUCCESS );
+}
+
+static psa_status_t psa_tls12_prf_set_key( psa_tls12_prf_key_derivation_t *prf,
+                                           const uint8_t *data,
+                                           size_t data_length )
+{
+    if( prf->state != PSA_TLS12_PRF_STATE_SEED_SET )
+        return( PSA_ERROR_BAD_STATE );
+
+    if( data_length != 0 )
+    {
+        prf->secret = mbedtls_calloc( 1, data_length );
+        if( prf->secret == NULL )
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+
+        memcpy( prf->secret, data, data_length );
+        prf->secret_length = data_length;
+    }
+
+    prf->state = PSA_TLS12_PRF_STATE_KEY_SET;
+
+    return( PSA_SUCCESS );
+}
+
+static psa_status_t psa_tls12_prf_set_label( psa_tls12_prf_key_derivation_t *prf,
+                                             const uint8_t *data,
+                                             size_t data_length )
+{
+    if( prf->state != PSA_TLS12_PRF_STATE_KEY_SET )
+        return( PSA_ERROR_BAD_STATE );
+
+    if( data_length != 0 )
+    {
+        prf->label = mbedtls_calloc( 1, data_length );
+        if( prf->label == NULL )
+            return( PSA_ERROR_INSUFFICIENT_MEMORY );
+
+        memcpy( prf->label, data, data_length );
+        prf->label_length = data_length;
+    }
+
+    prf->state = PSA_TLS12_PRF_STATE_LABEL_SET;
+
+    return( PSA_SUCCESS );
+}
+
+static psa_status_t psa_tls12_prf_input( psa_tls12_prf_key_derivation_t *prf,
+                                         psa_key_derivation_step_t step,
+                                         const uint8_t *data,
+                                         size_t data_length )
+{
+    switch( step )
+    {
+        case PSA_KEY_DERIVATION_INPUT_SEED:
+            return( psa_tls12_prf_set_seed( prf, data, data_length ) );
+        case PSA_KEY_DERIVATION_INPUT_SECRET:
+            return( psa_tls12_prf_set_key( prf, data, data_length ) );
+        case PSA_KEY_DERIVATION_INPUT_LABEL:
+            return( psa_tls12_prf_set_label( prf, data, data_length ) );
+        default:
+            return( PSA_ERROR_INVALID_ARGUMENT );
+    }
+}
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF) ||
+        * MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+static psa_status_t psa_tls12_prf_psk_to_ms_set_key(
+    psa_tls12_prf_key_derivation_t *prf,
+    const uint8_t *data,
+    size_t data_length )
+{
+    psa_status_t status;
+    uint8_t pms[ 4 + 2 * PSA_TLS12_PSK_TO_MS_PSK_MAX_SIZE ];
+    uint8_t *cur = pms;
+
+    if( data_length > PSA_TLS12_PSK_TO_MS_PSK_MAX_SIZE )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    /* Quoting RFC 4279, Section 2:
+     *
+     * The premaster secret is formed as follows: if the PSK is N octets
+     * long, concatenate a uint16 with the value N, N zero octets, a second
+     * uint16 with the value N, and the PSK itself.
+     */
+
+    *cur++ = ( data_length >> 8 ) & 0xff;
+    *cur++ = ( data_length >> 0 ) & 0xff;
+    memset( cur, 0, data_length );
+    cur += data_length;
+    *cur++ = pms[0];
+    *cur++ = pms[1];
+    memcpy( cur, data, data_length );
+    cur += data_length;
+
+    status = psa_tls12_prf_set_key( prf, pms, cur - pms );
+
+    mbedtls_platform_zeroize( pms, sizeof( pms ) );
+    return( status );
+}
+
+static psa_status_t psa_tls12_prf_psk_to_ms_input(
+    psa_tls12_prf_key_derivation_t *prf,
+    psa_key_derivation_step_t step,
+    const uint8_t *data,
+    size_t data_length )
+{
+    if( step == PSA_KEY_DERIVATION_INPUT_SECRET )
+    {
+        return( psa_tls12_prf_psk_to_ms_set_key( prf,
+                                                 data, data_length ) );
+    }
+
+    return( psa_tls12_prf_input( prf, step, data, data_length ) );
+}
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */
+
+/** Check whether the given key type is acceptable for the given
+ * input step of a key derivation.
+ *
+ * Secret inputs must have the type #PSA_KEY_TYPE_DERIVE.
+ * Non-secret inputs must have the type #PSA_KEY_TYPE_RAW_DATA.
+ * Both secret and non-secret inputs can alternatively have the type
+ * #PSA_KEY_TYPE_NONE, which is never the type of a key object, meaning
+ * that the input was passed as a buffer rather than via a key object.
+ */
+static int psa_key_derivation_check_input_type(
+    psa_key_derivation_step_t step,
+    psa_key_type_t key_type )
+{
+    switch( step )
+    {
+        case PSA_KEY_DERIVATION_INPUT_SECRET:
+            if( key_type == PSA_KEY_TYPE_DERIVE )
+                return( PSA_SUCCESS );
+            if( key_type == PSA_KEY_TYPE_NONE )
+                return( PSA_SUCCESS );
+            break;
+        case PSA_KEY_DERIVATION_INPUT_LABEL:
+        case PSA_KEY_DERIVATION_INPUT_SALT:
+        case PSA_KEY_DERIVATION_INPUT_INFO:
+        case PSA_KEY_DERIVATION_INPUT_SEED:
+            if( key_type == PSA_KEY_TYPE_RAW_DATA )
+                return( PSA_SUCCESS );
+            if( key_type == PSA_KEY_TYPE_NONE )
+                return( PSA_SUCCESS );
+            break;
+    }
+    return( PSA_ERROR_INVALID_ARGUMENT );
+}
+
+static psa_status_t psa_key_derivation_input_internal(
+    psa_key_derivation_operation_t *operation,
+    psa_key_derivation_step_t step,
+    psa_key_type_t key_type,
+    const uint8_t *data,
+    size_t data_length )
+{
+    psa_status_t status;
+    psa_algorithm_t kdf_alg = psa_key_derivation_get_kdf_alg( operation );
+
+    status = psa_key_derivation_check_input_type( step, key_type );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
+    if( PSA_ALG_IS_HKDF( kdf_alg ) )
+    {
+        status = psa_hkdf_input( &operation->ctx.hkdf,
+                                 PSA_ALG_HKDF_GET_HASH( kdf_alg ),
+                                 step, data, data_length );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_HKDF */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF)
+    if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) )
+    {
+        status = psa_tls12_prf_input( &operation->ctx.tls12_prf,
+                                      step, data, data_length );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF */
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
+    if( PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) )
+    {
+        status = psa_tls12_prf_psk_to_ms_input( &operation->ctx.tls12_prf,
+                                                step, data, data_length );
+    }
+    else
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */
+    {
+        /* This can't happen unless the operation object was not initialized */
+        (void) data;
+        (void) data_length;
+        (void) kdf_alg;
+        return( PSA_ERROR_BAD_STATE );
+    }
+
+exit:
+    if( status != PSA_SUCCESS )
+        psa_key_derivation_abort( operation );
+    return( status );
+}
+
+psa_status_t psa_key_derivation_input_bytes(
+    psa_key_derivation_operation_t *operation,
+    psa_key_derivation_step_t step,
+    const uint8_t *data,
+    size_t data_length )
+{
+    return( psa_key_derivation_input_internal( operation, step,
+                                               PSA_KEY_TYPE_NONE,
+                                               data, data_length ) );
+}
+
+psa_status_t psa_key_derivation_input_key(
+    psa_key_derivation_operation_t *operation,
+    psa_key_derivation_step_t step,
+    mbedtls_svc_key_id_t key )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    status = psa_get_and_lock_transparent_key_slot_with_policy(
+                 key, &slot, PSA_KEY_USAGE_DERIVE, operation->alg );
+    if( status != PSA_SUCCESS )
+    {
+        psa_key_derivation_abort( operation );
+        return( status );
+    }
+
+    /* Passing a key object as a SECRET input unlocks the permission
+     * to output to a key object. */
+    if( step == PSA_KEY_DERIVATION_INPUT_SECRET )
+        operation->can_output_key = 1;
+
+    status = psa_key_derivation_input_internal( operation,
+                                                step, slot->attr.type,
+                                                slot->key.data,
+                                                slot->key.bytes );
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+
+
+/****************************************************************/
+/* Key agreement */
+/****************************************************************/
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH)
+static psa_status_t psa_key_agreement_ecdh( const uint8_t *peer_key,
+                                            size_t peer_key_length,
+                                            const mbedtls_ecp_keypair *our_key,
+                                            uint8_t *shared_secret,
+                                            size_t shared_secret_size,
+                                            size_t *shared_secret_length )
+{
+    mbedtls_ecp_keypair *their_key = NULL;
+    mbedtls_ecdh_context ecdh;
+    psa_status_t status;
+    size_t bits = 0;
+    psa_ecc_family_t curve = mbedtls_ecc_group_to_psa( our_key->grp.id, &bits );
+    mbedtls_ecdh_init( &ecdh );
+
+    status = mbedtls_psa_ecp_load_representation(
+                 PSA_KEY_TYPE_ECC_PUBLIC_KEY(curve),
+                 bits,
+                 peer_key,
+                 peer_key_length,
+                 &their_key );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = mbedtls_to_psa_error(
+        mbedtls_ecdh_get_params( &ecdh, their_key, MBEDTLS_ECDH_THEIRS ) );
+    if( status != PSA_SUCCESS )
+        goto exit;
+    status = mbedtls_to_psa_error(
+        mbedtls_ecdh_get_params( &ecdh, our_key, MBEDTLS_ECDH_OURS ) );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = mbedtls_to_psa_error(
+        mbedtls_ecdh_calc_secret( &ecdh,
+                                  shared_secret_length,
+                                  shared_secret, shared_secret_size,
+                                  mbedtls_psa_get_random,
+                                  MBEDTLS_PSA_RANDOM_STATE ) );
+    if( status != PSA_SUCCESS )
+        goto exit;
+    if( PSA_BITS_TO_BYTES( bits ) != *shared_secret_length )
+        status = PSA_ERROR_CORRUPTION_DETECTED;
+
+exit:
+    if( status != PSA_SUCCESS )
+        mbedtls_platform_zeroize( shared_secret, shared_secret_size );
+    mbedtls_ecdh_free( &ecdh );
+    mbedtls_ecp_keypair_free( their_key );
+    mbedtls_free( their_key );
+
+    return( status );
+}
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_ECDH */
+
+#define PSA_KEY_AGREEMENT_MAX_SHARED_SECRET_SIZE MBEDTLS_ECP_MAX_BYTES
+
+static psa_status_t psa_key_agreement_raw_internal( psa_algorithm_t alg,
+                                                    psa_key_slot_t *private_key,
+                                                    const uint8_t *peer_key,
+                                                    size_t peer_key_length,
+                                                    uint8_t *shared_secret,
+                                                    size_t shared_secret_size,
+                                                    size_t *shared_secret_length )
+{
+    switch( alg )
+    {
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_ECDH)
+        case PSA_ALG_ECDH:
+            if( ! PSA_KEY_TYPE_IS_ECC_KEY_PAIR( private_key->attr.type ) )
+                return( PSA_ERROR_INVALID_ARGUMENT );
+            mbedtls_ecp_keypair *ecp = NULL;
+            psa_status_t status = mbedtls_psa_ecp_load_representation(
+                                      private_key->attr.type,
+                                      private_key->attr.bits,
+                                      private_key->key.data,
+                                      private_key->key.bytes,
+                                      &ecp );
+            if( status != PSA_SUCCESS )
+                return( status );
+            status = psa_key_agreement_ecdh( peer_key, peer_key_length,
+                                             ecp,
+                                             shared_secret, shared_secret_size,
+                                             shared_secret_length );
+            mbedtls_ecp_keypair_free( ecp );
+            mbedtls_free( ecp );
+            return( status );
+#endif /* MBEDTLS_PSA_BUILTIN_ALG_ECDH */
+        default:
+            (void) private_key;
+            (void) peer_key;
+            (void) peer_key_length;
+            (void) shared_secret;
+            (void) shared_secret_size;
+            (void) shared_secret_length;
+            return( PSA_ERROR_NOT_SUPPORTED );
+    }
+}
+
+/* Note that if this function fails, you must call psa_key_derivation_abort()
+ * to potentially free embedded data structures and wipe confidential data.
+ */
+static psa_status_t psa_key_agreement_internal( psa_key_derivation_operation_t *operation,
+                                                psa_key_derivation_step_t step,
+                                                psa_key_slot_t *private_key,
+                                                const uint8_t *peer_key,
+                                                size_t peer_key_length )
+{
+    psa_status_t status;
+    uint8_t shared_secret[PSA_KEY_AGREEMENT_MAX_SHARED_SECRET_SIZE];
+    size_t shared_secret_length = 0;
+    psa_algorithm_t ka_alg = PSA_ALG_KEY_AGREEMENT_GET_BASE( operation->alg );
+
+    /* Step 1: run the secret agreement algorithm to generate the shared
+     * secret. */
+    status = psa_key_agreement_raw_internal( ka_alg,
+                                             private_key,
+                                             peer_key, peer_key_length,
+                                             shared_secret,
+                                             sizeof( shared_secret ),
+                                             &shared_secret_length );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    /* Step 2: set up the key derivation to generate key material from
+     * the shared secret. A shared secret is permitted wherever a key
+     * of type DERIVE is permitted. */
+    status = psa_key_derivation_input_internal( operation, step,
+                                                PSA_KEY_TYPE_DERIVE,
+                                                shared_secret,
+                                                shared_secret_length );
+exit:
+    mbedtls_platform_zeroize( shared_secret, shared_secret_length );
+    return( status );
+}
+
+psa_status_t psa_key_derivation_key_agreement( psa_key_derivation_operation_t *operation,
+                                               psa_key_derivation_step_t step,
+                                               mbedtls_svc_key_id_t private_key,
+                                               const uint8_t *peer_key,
+                                               size_t peer_key_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot;
+
+    if( ! PSA_ALG_IS_KEY_AGREEMENT( operation->alg ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+    status = psa_get_and_lock_transparent_key_slot_with_policy(
+                 private_key, &slot, PSA_KEY_USAGE_DERIVE, operation->alg );
+    if( status != PSA_SUCCESS )
+        return( status );
+    status = psa_key_agreement_internal( operation, step,
+                                         slot,
+                                         peer_key, peer_key_length );
+    if( status != PSA_SUCCESS )
+        psa_key_derivation_abort( operation );
+    else
+    {
+        /* If a private key has been added as SECRET, we allow the derived
+         * key material to be used as a key in PSA Crypto. */
+        if( step == PSA_KEY_DERIVATION_INPUT_SECRET )
+            operation->can_output_key = 1;
+    }
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+psa_status_t psa_raw_key_agreement( psa_algorithm_t alg,
+                                    mbedtls_svc_key_id_t private_key,
+                                    const uint8_t *peer_key,
+                                    size_t peer_key_length,
+                                    uint8_t *output,
+                                    size_t output_size,
+                                    size_t *output_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_slot_t *slot = NULL;
+
+    if( ! PSA_ALG_IS_KEY_AGREEMENT( alg ) )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+    status = psa_get_and_lock_transparent_key_slot_with_policy(
+                 private_key, &slot, PSA_KEY_USAGE_DERIVE, alg );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    status = psa_key_agreement_raw_internal( alg, slot,
+                                             peer_key, peer_key_length,
+                                             output, output_size,
+                                             output_length );
+
+exit:
+    if( status != PSA_SUCCESS )
+    {
+        /* If an error happens and is not handled properly, the output
+         * may be used as a key to protect sensitive data. Arrange for such
+         * a key to be random, which is likely to result in decryption or
+         * verification errors. This is better than filling the buffer with
+         * some constant data such as zeros, which would result in the data
+         * being protected with a reproducible, easily knowable key.
+         */
+        psa_generate_random( output, output_size );
+        *output_length = output_size;
+    }
+
+    unlock_status = psa_unlock_key_slot( slot );
+
+    return( ( status == PSA_SUCCESS ) ? unlock_status : status );
+}
+
+
+
+/****************************************************************/
+/* Random generation */
+/****************************************************************/
+
+/** Initialize the PSA random generator.
+ */
+static void mbedtls_psa_random_init( mbedtls_psa_random_context_t *rng )
+{
+#if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+    memset( rng, 0, sizeof( *rng ) );
+#else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+
+    /* Set default configuration if
+     * mbedtls_psa_crypto_configure_entropy_sources() hasn't been called. */
+    if( rng->entropy_init == NULL )
+        rng->entropy_init = mbedtls_entropy_init;
+    if( rng->entropy_free == NULL )
+        rng->entropy_free = mbedtls_entropy_free;
+
+    rng->entropy_init( &rng->entropy );
+#if defined(MBEDTLS_PSA_INJECT_ENTROPY) && \
+    defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES)
+    /* The PSA entropy injection feature depends on using NV seed as an entropy
+     * source. Add NV seed as an entropy source for PSA entropy injection. */
+    mbedtls_entropy_add_source( &rng->entropy,
+                                mbedtls_nv_seed_poll, NULL,
+                                MBEDTLS_ENTROPY_BLOCK_SIZE,
+                                MBEDTLS_ENTROPY_SOURCE_STRONG );
+#endif
+
+    mbedtls_psa_drbg_init( MBEDTLS_PSA_RANDOM_STATE );
+#endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+}
+
+/** Deinitialize the PSA random generator.
+ */
+static void mbedtls_psa_random_free( mbedtls_psa_random_context_t *rng )
+{
+#if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+    memset( rng, 0, sizeof( *rng ) );
+#else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+    mbedtls_psa_drbg_free( MBEDTLS_PSA_RANDOM_STATE );
+    rng->entropy_free( &rng->entropy );
+#endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+}
+
+/** Seed the PSA random generator.
+ */
+static psa_status_t mbedtls_psa_random_seed( mbedtls_psa_random_context_t *rng )
+{
+#if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+    /* Do nothing: the external RNG seeds itself. */
+    (void) rng;
+    return( PSA_SUCCESS );
+#else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+    const unsigned char drbg_seed[] = "PSA";
+    int ret = mbedtls_psa_drbg_seed( &rng->entropy,
+                                     drbg_seed, sizeof( drbg_seed ) - 1 );
+    return mbedtls_to_psa_error( ret );
+#endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+}
+
+psa_status_t psa_generate_random( uint8_t *output,
+                                  size_t output_size )
+{
+    GUARD_MODULE_INITIALIZED;
+
+#if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+
+    size_t output_length = 0;
+    psa_status_t status = mbedtls_psa_external_get_random( &global_data.rng,
+                                                           output, output_size,
+                                                           &output_length );
+    if( status != PSA_SUCCESS )
+        return( status );
+    /* Breaking up a request into smaller chunks is currently not supported
+     * for the extrernal RNG interface. */
+    if( output_length != output_size )
+        return( PSA_ERROR_INSUFFICIENT_ENTROPY );
+    return( PSA_SUCCESS );
+
+#else /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+
+    while( output_size > 0 )
+    {
+        size_t request_size =
+            ( output_size > MBEDTLS_PSA_RANDOM_MAX_REQUEST ?
+              MBEDTLS_PSA_RANDOM_MAX_REQUEST :
+              output_size );
+        int ret = mbedtls_psa_get_random( MBEDTLS_PSA_RANDOM_STATE,
+                                          output, request_size );
+        if( ret != 0 )
+            return( mbedtls_to_psa_error( ret ) );
+        output_size -= request_size;
+        output += request_size;
+    }
+    return( PSA_SUCCESS );
+#endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+}
+
+/* Wrapper function allowing the classic API to use the PSA RNG.
+ *
+ * `mbedtls_psa_get_random(MBEDTLS_PSA_RANDOM_STATE, ...)` calls
+ * `psa_generate_random(...)`. The state parameter is ignored since the
+ * PSA API doesn't support passing an explicit state.
+ *
+ * In the non-external case, psa_generate_random() calls an
+ * `mbedtls_xxx_drbg_random` function which has exactly the same signature
+ * and semantics as mbedtls_psa_get_random(). As an optimization,
+ * instead of doing this back-and-forth between the PSA API and the
+ * classic API, psa_crypto_random_impl.h defines `mbedtls_psa_get_random`
+ * as a constant function pointer to `mbedtls_xxx_drbg_random`.
+ */
+#if defined (MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+int mbedtls_psa_get_random( void *p_rng,
+                            unsigned char *output,
+                            size_t output_size )
+{
+    /* This function takes a pointer to the RNG state because that's what
+     * classic mbedtls functions using an RNG expect. The PSA RNG manages
+     * its own state internally and doesn't let the caller access that state.
+     * So we just ignore the state parameter, and in practice we'll pass
+     * NULL. */
+    (void) p_rng;
+    psa_status_t status = psa_generate_random( output, output_size );
+    if( status == PSA_SUCCESS )
+        return( 0 );
+    else
+        return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
+}
+#endif /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
+
+#if defined(MBEDTLS_PSA_INJECT_ENTROPY)
+#include "mbedtls/entropy_poll.h"
+
+psa_status_t mbedtls_psa_inject_entropy( const uint8_t *seed,
+                                         size_t seed_size )
+{
+    if( global_data.initialized )
+        return( PSA_ERROR_NOT_PERMITTED );
+
+    if( ( ( seed_size < MBEDTLS_ENTROPY_MIN_PLATFORM ) ||
+          ( seed_size < MBEDTLS_ENTROPY_BLOCK_SIZE ) ) ||
+          ( seed_size > MBEDTLS_ENTROPY_MAX_SEED_SIZE ) )
+            return( PSA_ERROR_INVALID_ARGUMENT );
+
+    return( mbedtls_psa_storage_inject_entropy( seed, seed_size ) );
+}
+#endif /* MBEDTLS_PSA_INJECT_ENTROPY */
+
+/** Validate the key type and size for key generation
+ *
+ * \param  type  The key type
+ * \param  bits  The number of bits of the key
+ *
+ * \retval #PSA_SUCCESS
+ *         The key type and size are valid.
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ *         The size in bits of the key is not valid.
+ * \retval #PSA_ERROR_NOT_SUPPORTED
+ *         The type and/or the size in bits of the key or the combination of
+ *         the two is not supported.
+ */
+static psa_status_t psa_validate_key_type_and_size_for_key_generation(
+    psa_key_type_t type, size_t bits )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+    if( key_type_is_raw_bytes( type ) )
+    {
+        status = validate_unstructured_key_bit_size( type, bits );
+        if( status != PSA_SUCCESS )
+            return( status );
+    }
+    else
+#if defined(PSA_WANT_KEY_TYPE_RSA_KEY_PAIR)
+    if( PSA_KEY_TYPE_IS_RSA( type ) && PSA_KEY_TYPE_IS_KEY_PAIR( type ) )
+    {
+        if( bits > PSA_VENDOR_RSA_MAX_KEY_BITS )
+            return( PSA_ERROR_NOT_SUPPORTED );
+
+        /* Accept only byte-aligned keys, for the same reasons as
+         * in psa_import_rsa_key(). */
+        if( bits % 8 != 0 )
+            return( PSA_ERROR_NOT_SUPPORTED );
+    }
+    else
+#endif /* defined(PSA_WANT_KEY_TYPE_RSA_KEY_PAIR) */
+
+#if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR)
+    if( PSA_KEY_TYPE_IS_ECC( type ) && PSA_KEY_TYPE_IS_KEY_PAIR( type ) )
+    {
+        /* To avoid empty block, return successfully here. */
+        return( PSA_SUCCESS );
+    }
+    else
+#endif /* defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR) */
+    {
+        return( PSA_ERROR_NOT_SUPPORTED );
+    }
+
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_generate_key_internal(
+    const psa_key_attributes_t *attributes,
+    uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length )
+{
+    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    psa_key_type_t type = attributes->core.type;
+
+    if( ( attributes->domain_parameters == NULL ) &&
+        ( attributes->domain_parameters_size != 0 ) )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    if( key_type_is_raw_bytes( type ) )
+    {
+        status = psa_generate_random( key_buffer, key_buffer_size );
+        if( status != PSA_SUCCESS )
+            return( status );
+
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES)
+        if( type == PSA_KEY_TYPE_DES )
+            psa_des_set_key_parity( key_buffer, key_buffer_size );
+#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DES */
+    }
+    else
+
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) && \
+    defined(MBEDTLS_GENPRIME)
+    if ( type == PSA_KEY_TYPE_RSA_KEY_PAIR )
+    {
+        return( mbedtls_psa_rsa_generate_key( attributes,
+                                              key_buffer,
+                                              key_buffer_size,
+                                              key_buffer_length ) );
+    }
+    else
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR)
+        * defined(MBEDTLS_GENPRIME) */
+
+#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR)
+    if ( PSA_KEY_TYPE_IS_ECC( type ) && PSA_KEY_TYPE_IS_KEY_PAIR( type ) )
+    {
+        return( mbedtls_psa_ecp_generate_key( attributes,
+                                              key_buffer,
+                                              key_buffer_size,
+                                              key_buffer_length ) );
+    }
+    else
+#endif /* defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR) */
+    {
+        (void)key_buffer_length;
+        return( PSA_ERROR_NOT_SUPPORTED );
+    }
+
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_generate_key( const psa_key_attributes_t *attributes,
+                               mbedtls_svc_key_id_t *key )
+{
+    psa_status_t status;
+    psa_key_slot_t *slot = NULL;
+    psa_se_drv_table_entry_t *driver = NULL;
+    size_t key_buffer_size;
+
+    *key = MBEDTLS_SVC_KEY_ID_INIT;
+
+    /* Reject any attempt to create a zero-length key so that we don't
+     * risk tripping up later, e.g. on a malloc(0) that returns NULL. */
+    if( psa_get_key_bits( attributes ) == 0 )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    status = psa_start_key_creation( PSA_KEY_CREATION_GENERATE, attributes,
+                                     &slot, &driver );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    /* In the case of a transparent key or an opaque key stored in local
+     * storage (thus not in the case of generating a key in a secure element
+     * or cryptoprocessor with storage), we have to allocate a buffer to
+     * hold the generated key material. */
+    if( slot->key.data == NULL )
+    {
+        if ( PSA_KEY_LIFETIME_GET_LOCATION( attributes->core.lifetime ) ==
+             PSA_KEY_LOCATION_LOCAL_STORAGE )
+        {
+            status = psa_validate_key_type_and_size_for_key_generation(
+                attributes->core.type, attributes->core.bits );
+            if( status != PSA_SUCCESS )
+                goto exit;
+
+            key_buffer_size = PSA_EXPORT_KEY_OUTPUT_SIZE(
+                                  attributes->core.type,
+                                  attributes->core.bits );
+        }
+        else
+        {
+            status = psa_driver_wrapper_get_key_buffer_size(
+                         attributes, &key_buffer_size );
+            if( status != PSA_SUCCESS )
+                goto exit;
+        }
+
+        status = psa_allocate_buffer_to_slot( slot, key_buffer_size );
+        if( status != PSA_SUCCESS )
+            goto exit;
+    }
+
+    status = psa_driver_wrapper_generate_key( attributes,
+        slot->key.data, slot->key.bytes, &slot->key.bytes );
+
+    if( status != PSA_SUCCESS )
+        psa_remove_key_data_from_memory( slot );
+
+exit:
+    if( status == PSA_SUCCESS )
+        status = psa_finish_key_creation( slot, driver, key );
+    if( status != PSA_SUCCESS )
+        psa_fail_key_creation( slot, driver );
+
+    return( status );
+}
+
+/****************************************************************/
+/* Module setup */
+/****************************************************************/
+
+#if !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
+psa_status_t mbedtls_psa_crypto_configure_entropy_sources(
+    void (* entropy_init )( mbedtls_entropy_context *ctx ),
+    void (* entropy_free )( mbedtls_entropy_context *ctx ) )
+{
+    if( global_data.rng_state != RNG_NOT_INITIALIZED )
+        return( PSA_ERROR_BAD_STATE );
+    global_data.rng.entropy_init = entropy_init;
+    global_data.rng.entropy_free = entropy_free;
+    return( PSA_SUCCESS );
+}
+#endif /* !defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG) */
+
+void mbedtls_psa_crypto_free( void )
+{
+    psa_wipe_all_key_slots( );
+    if( global_data.rng_state != RNG_NOT_INITIALIZED )
+    {
+        mbedtls_psa_random_free( &global_data.rng );
+    }
+    /* Wipe all remaining data, including configuration.
+     * In particular, this sets all state indicator to the value
+     * indicating "uninitialized". */
+    mbedtls_platform_zeroize( &global_data, sizeof( global_data ) );
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    /* Unregister all secure element drivers, so that we restart from
+     * a pristine state. */
+    psa_unregister_all_se_drivers( );
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+}
+
+#if defined(PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS)
+/** Recover a transaction that was interrupted by a power failure.
+ *
+ * This function is called during initialization, before psa_crypto_init()
+ * returns. If this function returns a failure status, the initialization
+ * fails.
+ */
+static psa_status_t psa_crypto_recover_transaction(
+    const psa_crypto_transaction_t *transaction )
+{
+    switch( transaction->unknown.type )
+    {
+        case PSA_CRYPTO_TRANSACTION_CREATE_KEY:
+        case PSA_CRYPTO_TRANSACTION_DESTROY_KEY:
+            /* TODO - fall through to the failure case until this
+             * is implemented.
+             * https://github.com/ARMmbed/mbed-crypto/issues/218
+             */
+        default:
+            /* We found an unsupported transaction in the storage.
+             * We don't know what state the storage is in. Give up. */
+            return( PSA_ERROR_DATA_INVALID );
+    }
+}
+#endif /* PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS */
+
+psa_status_t psa_crypto_init( void )
+{
+    psa_status_t status;
+
+    /* Double initialization is explicitly allowed. */
+    if( global_data.initialized != 0 )
+        return( PSA_SUCCESS );
+
+    /* Initialize and seed the random generator. */
+    mbedtls_psa_random_init( &global_data.rng );
+    global_data.rng_state = RNG_INITIALIZED;
+    status = mbedtls_psa_random_seed( &global_data.rng );
+    if( status != PSA_SUCCESS )
+        goto exit;
+    global_data.rng_state = RNG_SEEDED;
+
+    status = psa_initialize_key_slots( );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
+    status = psa_init_all_se_drivers( );
+    if( status != PSA_SUCCESS )
+        goto exit;
+#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
+
+#if defined(PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS)
+    status = psa_crypto_load_transaction( );
+    if( status == PSA_SUCCESS )
+    {
+        status = psa_crypto_recover_transaction( &psa_crypto_transaction );
+        if( status != PSA_SUCCESS )
+            goto exit;
+        status = psa_crypto_stop_transaction( );
+    }
+    else if( status == PSA_ERROR_DOES_NOT_EXIST )
+    {
+        /* There's no transaction to complete. It's all good. */
+        status = PSA_SUCCESS;
+    }
+#endif /* PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS */
+
+    /* All done. */
+    global_data.initialized = 1;
+
+exit:
+    if( status != PSA_SUCCESS )
+        mbedtls_psa_crypto_free( );
+    return( status );
+}
+
+#endif /* MBEDTLS_PSA_CRYPTO_C */