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+/**
+ * \file pk.h
+ *
+ * \brief Public Key abstraction layer
+ */
+/*
+ * 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.
+ */
+
+#ifndef MBEDTLS_PK_H
+#define MBEDTLS_PK_H
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#include "mbedtls/md.h"
+
+#if defined(MBEDTLS_RSA_C)
+#include "mbedtls/rsa.h"
+#endif
+
+#if defined(MBEDTLS_ECP_C)
+#include "mbedtls/ecp.h"
+#endif
+
+#if defined(MBEDTLS_ECDSA_C)
+#include "mbedtls/ecdsa.h"
+#endif
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+#include "psa/crypto.h"
+#endif
+
+#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
+ !defined(inline) && !defined(__cplusplus)
+#define inline __inline
+#endif
+
+#define MBEDTLS_ERR_PK_ALLOC_FAILED -0x3F80 /**< Memory allocation failed. */
+#define MBEDTLS_ERR_PK_TYPE_MISMATCH -0x3F00 /**< Type mismatch, eg attempt to encrypt with an ECDSA key */
+#define MBEDTLS_ERR_PK_BAD_INPUT_DATA -0x3E80 /**< Bad input parameters to function. */
+#define MBEDTLS_ERR_PK_FILE_IO_ERROR -0x3E00 /**< Read/write of file failed. */
+#define MBEDTLS_ERR_PK_KEY_INVALID_VERSION -0x3D80 /**< Unsupported key version */
+#define MBEDTLS_ERR_PK_KEY_INVALID_FORMAT -0x3D00 /**< Invalid key tag or value. */
+#define MBEDTLS_ERR_PK_UNKNOWN_PK_ALG -0x3C80 /**< Key algorithm is unsupported (only RSA and EC are supported). */
+#define MBEDTLS_ERR_PK_PASSWORD_REQUIRED -0x3C00 /**< Private key password can't be empty. */
+#define MBEDTLS_ERR_PK_PASSWORD_MISMATCH -0x3B80 /**< Given private key password does not allow for correct decryption. */
+#define MBEDTLS_ERR_PK_INVALID_PUBKEY -0x3B00 /**< The pubkey tag or value is invalid (only RSA and EC are supported). */
+#define MBEDTLS_ERR_PK_INVALID_ALG -0x3A80 /**< The algorithm tag or value is invalid. */
+#define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00 /**< Elliptic curve is unsupported (only NIST curves are supported). */
+#define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980 /**< Unavailable feature, e.g. RSA disabled for RSA key. */
+#define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH -0x3900 /**< The buffer contains a valid signature followed by more data. */
+
+/* MBEDTLS_ERR_PK_HW_ACCEL_FAILED is deprecated and should not be used. */
+#define MBEDTLS_ERR_PK_HW_ACCEL_FAILED -0x3880 /**< PK hardware accelerator failed. */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief Public key types
+ */
+typedef enum {
+ MBEDTLS_PK_NONE=0,
+ MBEDTLS_PK_RSA,
+ MBEDTLS_PK_ECKEY,
+ MBEDTLS_PK_ECKEY_DH,
+ MBEDTLS_PK_ECDSA,
+ MBEDTLS_PK_RSA_ALT,
+ MBEDTLS_PK_RSASSA_PSS,
+ MBEDTLS_PK_OPAQUE,
+} mbedtls_pk_type_t;
+
+/**
+ * \brief Options for RSASSA-PSS signature verification.
+ * See \c mbedtls_rsa_rsassa_pss_verify_ext()
+ */
+typedef struct mbedtls_pk_rsassa_pss_options
+{
+ mbedtls_md_type_t mgf1_hash_id;
+ int expected_salt_len;
+
+} mbedtls_pk_rsassa_pss_options;
+
+/**
+ * \brief Maximum size of a signature made by mbedtls_pk_sign().
+ */
+/* We need to set MBEDTLS_PK_SIGNATURE_MAX_SIZE to the maximum signature
+ * size among the supported signature types. Do it by starting at 0,
+ * then incrementally increasing to be large enough for each supported
+ * signature mechanism.
+ *
+ * The resulting value can be 0, for example if MBEDTLS_ECDH_C is enabled
+ * (which allows the pk module to be included) but neither MBEDTLS_ECDSA_C
+ * nor MBEDTLS_RSA_C nor any opaque signature mechanism (PSA or RSA_ALT).
+ */
+#define MBEDTLS_PK_SIGNATURE_MAX_SIZE 0
+
+#if ( defined(MBEDTLS_RSA_C) || defined(MBEDTLS_PK_RSA_ALT_SUPPORT) ) && \
+ MBEDTLS_MPI_MAX_SIZE > MBEDTLS_PK_SIGNATURE_MAX_SIZE
+/* For RSA, the signature can be as large as the bignum module allows.
+ * For RSA_ALT, the signature size is not necessarily tied to what the
+ * bignum module can do, but in the absence of any specific setting,
+ * we use that (rsa_alt_sign_wrap in pk_wrap will check). */
+#undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
+#define MBEDTLS_PK_SIGNATURE_MAX_SIZE MBEDTLS_MPI_MAX_SIZE
+#endif
+
+#if defined(MBEDTLS_ECDSA_C) && \
+ MBEDTLS_ECDSA_MAX_LEN > MBEDTLS_PK_SIGNATURE_MAX_SIZE
+/* For ECDSA, the ecdsa module exports a constant for the maximum
+ * signature size. */
+#undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
+#define MBEDTLS_PK_SIGNATURE_MAX_SIZE MBEDTLS_ECDSA_MAX_LEN
+#endif
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+#if PSA_SIGNATURE_MAX_SIZE > MBEDTLS_PK_SIGNATURE_MAX_SIZE
+/* PSA_SIGNATURE_MAX_SIZE is the maximum size of a signature made
+ * through the PSA API in the PSA representation. */
+#undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
+#define MBEDTLS_PK_SIGNATURE_MAX_SIZE PSA_SIGNATURE_MAX_SIZE
+#endif
+
+#if PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE + 11 > MBEDTLS_PK_SIGNATURE_MAX_SIZE
+/* The Mbed TLS representation is different for ECDSA signatures:
+ * PSA uses the raw concatenation of r and s,
+ * whereas Mbed TLS uses the ASN.1 representation (SEQUENCE of two INTEGERs).
+ * Add the overhead of ASN.1: up to (1+2) + 2 * (1+2+1) for the
+ * types, lengths (represented by up to 2 bytes), and potential leading
+ * zeros of the INTEGERs and the SEQUENCE. */
+#undef MBEDTLS_PK_SIGNATURE_MAX_SIZE
+#define MBEDTLS_PK_SIGNATURE_MAX_SIZE ( PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE + 11 )
+#endif
+#endif /* defined(MBEDTLS_USE_PSA_CRYPTO) */
+
+/**
+ * \brief Types for interfacing with the debug module
+ */
+typedef enum
+{
+ MBEDTLS_PK_DEBUG_NONE = 0,
+ MBEDTLS_PK_DEBUG_MPI,
+ MBEDTLS_PK_DEBUG_ECP,
+} mbedtls_pk_debug_type;
+
+/**
+ * \brief Item to send to the debug module
+ */
+typedef struct mbedtls_pk_debug_item
+{
+ mbedtls_pk_debug_type type;
+ const char *name;
+ void *value;
+} mbedtls_pk_debug_item;
+
+/** Maximum number of item send for debugging, plus 1 */
+#define MBEDTLS_PK_DEBUG_MAX_ITEMS 3
+
+/**
+ * \brief Public key information and operations
+ */
+typedef struct mbedtls_pk_info_t mbedtls_pk_info_t;
+
+/**
+ * \brief Public key container
+ */
+typedef struct mbedtls_pk_context
+{
+ const mbedtls_pk_info_t * pk_info; /**< Public key information */
+ void * pk_ctx; /**< Underlying public key context */
+} mbedtls_pk_context;
+
+#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
+/**
+ * \brief Context for resuming operations
+ */
+typedef struct
+{
+ const mbedtls_pk_info_t * pk_info; /**< Public key information */
+ void * rs_ctx; /**< Underlying restart context */
+} mbedtls_pk_restart_ctx;
+#else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+/* Now we can declare functions that take a pointer to that */
+typedef void mbedtls_pk_restart_ctx;
+#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+
+#if defined(MBEDTLS_RSA_C)
+/**
+ * Quick access to an RSA context inside a PK context.
+ *
+ * \warning You must make sure the PK context actually holds an RSA context
+ * before using this function!
+ */
+static inline mbedtls_rsa_context *mbedtls_pk_rsa( const mbedtls_pk_context pk )
+{
+ return( (mbedtls_rsa_context *) (pk).pk_ctx );
+}
+#endif /* MBEDTLS_RSA_C */
+
+#if defined(MBEDTLS_ECP_C)
+/**
+ * Quick access to an EC context inside a PK context.
+ *
+ * \warning You must make sure the PK context actually holds an EC context
+ * before using this function!
+ */
+static inline mbedtls_ecp_keypair *mbedtls_pk_ec( const mbedtls_pk_context pk )
+{
+ return( (mbedtls_ecp_keypair *) (pk).pk_ctx );
+}
+#endif /* MBEDTLS_ECP_C */
+
+#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
+/**
+ * \brief Types for RSA-alt abstraction
+ */
+typedef int (*mbedtls_pk_rsa_alt_decrypt_func)( void *ctx, int mode, size_t *olen,
+ const unsigned char *input, unsigned char *output,
+ size_t output_max_len );
+typedef int (*mbedtls_pk_rsa_alt_sign_func)( void *ctx,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
+ int mode, mbedtls_md_type_t md_alg, unsigned int hashlen,
+ const unsigned char *hash, unsigned char *sig );
+typedef size_t (*mbedtls_pk_rsa_alt_key_len_func)( void *ctx );
+#endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */
+
+/**
+ * \brief Return information associated with the given PK type
+ *
+ * \param pk_type PK type to search for.
+ *
+ * \return The PK info associated with the type or NULL if not found.
+ */
+const mbedtls_pk_info_t *mbedtls_pk_info_from_type( mbedtls_pk_type_t pk_type );
+
+/**
+ * \brief Initialize a #mbedtls_pk_context (as NONE).
+ *
+ * \param ctx The context to initialize.
+ * This must not be \c NULL.
+ */
+void mbedtls_pk_init( mbedtls_pk_context *ctx );
+
+/**
+ * \brief Free the components of a #mbedtls_pk_context.
+ *
+ * \param ctx The context to clear. It must have been initialized.
+ * If this is \c NULL, this function does nothing.
+ *
+ * \note For contexts that have been set up with
+ * mbedtls_pk_setup_opaque(), this does not free the underlying
+ * PSA key and you still need to call psa_destroy_key()
+ * independently if you want to destroy that key.
+ */
+void mbedtls_pk_free( mbedtls_pk_context *ctx );
+
+#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
+/**
+ * \brief Initialize a restart context
+ *
+ * \param ctx The context to initialize.
+ * This must not be \c NULL.
+ */
+void mbedtls_pk_restart_init( mbedtls_pk_restart_ctx *ctx );
+
+/**
+ * \brief Free the components of a restart context
+ *
+ * \param ctx The context to clear. It must have been initialized.
+ * If this is \c NULL, this function does nothing.
+ */
+void mbedtls_pk_restart_free( mbedtls_pk_restart_ctx *ctx );
+#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+
+/**
+ * \brief Initialize a PK context with the information given
+ * and allocates the type-specific PK subcontext.
+ *
+ * \param ctx Context to initialize. It must not have been set
+ * up yet (type #MBEDTLS_PK_NONE).
+ * \param info Information to use
+ *
+ * \return 0 on success,
+ * MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input,
+ * MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure.
+ *
+ * \note For contexts holding an RSA-alt key, use
+ * \c mbedtls_pk_setup_rsa_alt() instead.
+ */
+int mbedtls_pk_setup( mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info );
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+/**
+ * \brief Initialize a PK context to wrap a PSA key.
+ *
+ * \note This function replaces mbedtls_pk_setup() for contexts
+ * that wrap a (possibly opaque) PSA key instead of
+ * storing and manipulating the key material directly.
+ *
+ * \param ctx The context to initialize. It must be empty (type NONE).
+ * \param key The PSA key to wrap, which must hold an ECC key pair
+ * (see notes below).
+ *
+ * \note The wrapped key must remain valid as long as the
+ * wrapping PK context is in use, that is at least between
+ * the point this function is called and the point
+ * mbedtls_pk_free() is called on this context. The wrapped
+ * key might then be independently used or destroyed.
+ *
+ * \note This function is currently only available for ECC key
+ * pairs (that is, ECC keys containing private key material).
+ * Support for other key types may be added later.
+ *
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input
+ * (context already used, invalid key identifier).
+ * \return #MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE if the key is not an
+ * ECC key pair.
+ * \return #MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure.
+ */
+int mbedtls_pk_setup_opaque( mbedtls_pk_context *ctx,
+ const psa_key_id_t key );
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
+/**
+ * \brief Initialize an RSA-alt context
+ *
+ * \param ctx Context to initialize. It must not have been set
+ * up yet (type #MBEDTLS_PK_NONE).
+ * \param key RSA key pointer
+ * \param decrypt_func Decryption function
+ * \param sign_func Signing function
+ * \param key_len_func Function returning key length in bytes
+ *
+ * \return 0 on success, or MBEDTLS_ERR_PK_BAD_INPUT_DATA if the
+ * context wasn't already initialized as RSA_ALT.
+ *
+ * \note This function replaces \c mbedtls_pk_setup() for RSA-alt.
+ */
+int mbedtls_pk_setup_rsa_alt( mbedtls_pk_context *ctx, void * key,
+ mbedtls_pk_rsa_alt_decrypt_func decrypt_func,
+ mbedtls_pk_rsa_alt_sign_func sign_func,
+ mbedtls_pk_rsa_alt_key_len_func key_len_func );
+#endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */
+
+/**
+ * \brief Get the size in bits of the underlying key
+ *
+ * \param ctx The context to query. It must have been initialized.
+ *
+ * \return Key size in bits, or 0 on error
+ */
+size_t mbedtls_pk_get_bitlen( const mbedtls_pk_context *ctx );
+
+/**
+ * \brief Get the length in bytes of the underlying key
+ *
+ * \param ctx The context to query. It must have been initialized.
+ *
+ * \return Key length in bytes, or 0 on error
+ */
+static inline size_t mbedtls_pk_get_len( const mbedtls_pk_context *ctx )
+{
+ return( ( mbedtls_pk_get_bitlen( ctx ) + 7 ) / 8 );
+}
+
+/**
+ * \brief Tell if a context can do the operation given by type
+ *
+ * \param ctx The context to query. It must have been initialized.
+ * \param type The desired type.
+ *
+ * \return 1 if the context can do operations on the given type.
+ * \return 0 if the context cannot do the operations on the given
+ * type. This is always the case for a context that has
+ * been initialized but not set up, or that has been
+ * cleared with mbedtls_pk_free().
+ */
+int mbedtls_pk_can_do( const mbedtls_pk_context *ctx, mbedtls_pk_type_t type );
+
+/**
+ * \brief Verify signature (including padding if relevant).
+ *
+ * \param ctx The PK context to use. It must have been set up.
+ * \param md_alg Hash algorithm used (see notes)
+ * \param hash Hash of the message to sign
+ * \param hash_len Hash length or 0 (see notes)
+ * \param sig Signature to verify
+ * \param sig_len Signature length
+ *
+ * \return 0 on success (signature is valid),
+ * #MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if there is a valid
+ * signature in sig but its length is less than \p siglen,
+ * or a specific error code.
+ *
+ * \note For RSA keys, the default padding type is PKCS#1 v1.5.
+ * Use \c mbedtls_pk_verify_ext( MBEDTLS_PK_RSASSA_PSS, ... )
+ * to verify RSASSA_PSS signatures.
+ *
+ * \note If hash_len is 0, then the length associated with md_alg
+ * is used instead, or an error returned if it is invalid.
+ *
+ * \note md_alg may be MBEDTLS_MD_NONE, only if hash_len != 0
+ */
+int mbedtls_pk_verify( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hash_len,
+ const unsigned char *sig, size_t sig_len );
+
+/**
+ * \brief Restartable version of \c mbedtls_pk_verify()
+ *
+ * \note Performs the same job as \c mbedtls_pk_verify(), but can
+ * return early and restart according to the limit set with
+ * \c mbedtls_ecp_set_max_ops() to reduce blocking for ECC
+ * operations. For RSA, same as \c mbedtls_pk_verify().
+ *
+ * \param ctx The PK context to use. It must have been set up.
+ * \param md_alg Hash algorithm used (see notes)
+ * \param hash Hash of the message to sign
+ * \param hash_len Hash length or 0 (see notes)
+ * \param sig Signature to verify
+ * \param sig_len Signature length
+ * \param rs_ctx Restart context (NULL to disable restart)
+ *
+ * \return See \c mbedtls_pk_verify(), or
+ * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
+ * operations was reached: see \c mbedtls_ecp_set_max_ops().
+ */
+int mbedtls_pk_verify_restartable( mbedtls_pk_context *ctx,
+ mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hash_len,
+ const unsigned char *sig, size_t sig_len,
+ mbedtls_pk_restart_ctx *rs_ctx );
+
+/**
+ * \brief Verify signature, with options.
+ * (Includes verification of the padding depending on type.)
+ *
+ * \param type Signature type (inc. possible padding type) to verify
+ * \param options Pointer to type-specific options, or NULL
+ * \param ctx The PK context to use. It must have been set up.
+ * \param md_alg Hash algorithm used (see notes)
+ * \param hash Hash of the message to sign
+ * \param hash_len Hash length or 0 (see notes)
+ * \param sig Signature to verify
+ * \param sig_len Signature length
+ *
+ * \return 0 on success (signature is valid),
+ * #MBEDTLS_ERR_PK_TYPE_MISMATCH if the PK context can't be
+ * used for this type of signatures,
+ * #MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if there is a valid
+ * signature in sig but its length is less than \p siglen,
+ * or a specific error code.
+ *
+ * \note If hash_len is 0, then the length associated with md_alg
+ * is used instead, or an error returned if it is invalid.
+ *
+ * \note md_alg may be MBEDTLS_MD_NONE, only if hash_len != 0
+ *
+ * \note If type is MBEDTLS_PK_RSASSA_PSS, then options must point
+ * to a mbedtls_pk_rsassa_pss_options structure,
+ * otherwise it must be NULL.
+ */
+int mbedtls_pk_verify_ext( mbedtls_pk_type_t type, const void *options,
+ mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hash_len,
+ const unsigned char *sig, size_t sig_len );
+
+/**
+ * \brief Make signature, including padding if relevant.
+ *
+ * \param ctx The PK context to use. It must have been set up
+ * with a private key.
+ * \param md_alg Hash algorithm used (see notes)
+ * \param hash Hash of the message to sign
+ * \param hash_len Hash length or 0 (see notes)
+ * \param sig Place to write the signature.
+ * It must have enough room for the signature.
+ * #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
+ * You may use a smaller buffer if it is large enough
+ * given the key type.
+ * \param sig_len On successful return,
+ * the number of bytes written to \p sig.
+ * \param f_rng RNG function
+ * \param p_rng RNG parameter
+ *
+ * \return 0 on success, or a specific error code.
+ *
+ * \note For RSA keys, the default padding type is PKCS#1 v1.5.
+ * There is no interface in the PK module to make RSASSA-PSS
+ * signatures yet.
+ *
+ * \note If hash_len is 0, then the length associated with md_alg
+ * is used instead, or an error returned if it is invalid.
+ *
+ * \note For RSA, md_alg may be MBEDTLS_MD_NONE if hash_len != 0.
+ * For ECDSA, md_alg may never be MBEDTLS_MD_NONE.
+ */
+int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hash_len,
+ unsigned char *sig, size_t *sig_len,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
+
+/**
+ * \brief Restartable version of \c mbedtls_pk_sign()
+ *
+ * \note Performs the same job as \c mbedtls_pk_sign(), but can
+ * return early and restart according to the limit set with
+ * \c mbedtls_ecp_set_max_ops() to reduce blocking for ECC
+ * operations. For RSA, same as \c mbedtls_pk_sign().
+ *
+ * \param ctx The PK context to use. It must have been set up
+ * with a private key.
+ * \param md_alg Hash algorithm used (see notes for mbedtls_pk_sign())
+ * \param hash Hash of the message to sign
+ * \param hash_len Hash length or 0 (see notes for mbedtls_pk_sign())
+ * \param sig Place to write the signature.
+ * It must have enough room for the signature.
+ * #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
+ * You may use a smaller buffer if it is large enough
+ * given the key type.
+ * \param sig_len On successful return,
+ * the number of bytes written to \p sig.
+ * \param f_rng RNG function
+ * \param p_rng RNG parameter
+ * \param rs_ctx Restart context (NULL to disable restart)
+ *
+ * \return See \c mbedtls_pk_sign().
+ * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
+ * operations was reached: see \c mbedtls_ecp_set_max_ops().
+ */
+int mbedtls_pk_sign_restartable( mbedtls_pk_context *ctx,
+ mbedtls_md_type_t md_alg,
+ const unsigned char *hash, size_t hash_len,
+ unsigned char *sig, size_t *sig_len,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
+ mbedtls_pk_restart_ctx *rs_ctx );
+
+/**
+ * \brief Decrypt message (including padding if relevant).
+ *
+ * \param ctx The PK context to use. It must have been set up
+ * with a private key.
+ * \param input Input to decrypt
+ * \param ilen Input size
+ * \param output Decrypted output
+ * \param olen Decrypted message length
+ * \param osize Size of the output buffer
+ * \param f_rng RNG function
+ * \param p_rng RNG parameter
+ *
+ * \note For RSA keys, the default padding type is PKCS#1 v1.5.
+ *
+ * \return 0 on success, or a specific error code.
+ */
+int mbedtls_pk_decrypt( mbedtls_pk_context *ctx,
+ const unsigned char *input, size_t ilen,
+ unsigned char *output, size_t *olen, size_t osize,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
+
+/**
+ * \brief Encrypt message (including padding if relevant).
+ *
+ * \param ctx The PK context to use. It must have been set up.
+ * \param input Message to encrypt
+ * \param ilen Message size
+ * \param output Encrypted output
+ * \param olen Encrypted output length
+ * \param osize Size of the output buffer
+ * \param f_rng RNG function
+ * \param p_rng RNG parameter
+ *
+ * \note For RSA keys, the default padding type is PKCS#1 v1.5.
+ *
+ * \return 0 on success, or a specific error code.
+ */
+int mbedtls_pk_encrypt( mbedtls_pk_context *ctx,
+ const unsigned char *input, size_t ilen,
+ unsigned char *output, size_t *olen, size_t osize,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
+
+/**
+ * \brief Check if a public-private pair of keys matches.
+ *
+ * \param pub Context holding a public key.
+ * \param prv Context holding a private (and public) key.
+ *
+ * \return \c 0 on success (keys were checked and match each other).
+ * \return #MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE if the keys could not
+ * be checked - in that case they may or may not match.
+ * \return #MBEDTLS_ERR_PK_BAD_INPUT_DATA if a context is invalid.
+ * \return Another non-zero value if the keys do not match.
+ */
+int mbedtls_pk_check_pair( const mbedtls_pk_context *pub, const mbedtls_pk_context *prv );
+
+/**
+ * \brief Export debug information
+ *
+ * \param ctx The PK context to use. It must have been initialized.
+ * \param items Place to write debug items
+ *
+ * \return 0 on success or MBEDTLS_ERR_PK_BAD_INPUT_DATA
+ */
+int mbedtls_pk_debug( const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items );
+
+/**
+ * \brief Access the type name
+ *
+ * \param ctx The PK context to use. It must have been initialized.
+ *
+ * \return Type name on success, or "invalid PK"
+ */
+const char * mbedtls_pk_get_name( const mbedtls_pk_context *ctx );
+
+/**
+ * \brief Get the key type
+ *
+ * \param ctx The PK context to use. It must have been initialized.
+ *
+ * \return Type on success.
+ * \return #MBEDTLS_PK_NONE for a context that has not been set up.
+ */
+mbedtls_pk_type_t mbedtls_pk_get_type( const mbedtls_pk_context *ctx );
+
+#if defined(MBEDTLS_PK_PARSE_C)
+/** \ingroup pk_module */
+/**
+ * \brief Parse a private key in PEM or DER format
+ *
+ * \param ctx The PK context to fill. It must have been initialized
+ * but not set up.
+ * \param key Input buffer to parse.
+ * The buffer must contain the input exactly, with no
+ * extra trailing material. For PEM, the buffer must
+ * contain a null-terminated string.
+ * \param keylen Size of \b key in bytes.
+ * For PEM data, this includes the terminating null byte,
+ * so \p keylen must be equal to `strlen(key) + 1`.
+ * \param pwd Optional password for decryption.
+ * Pass \c NULL if expecting a non-encrypted key.
+ * Pass a string of \p pwdlen bytes if expecting an encrypted
+ * key; a non-encrypted key will also be accepted.
+ * The empty password is not supported.
+ * \param pwdlen Size of the password in bytes.
+ * Ignored if \p pwd is \c NULL.
+ *
+ * \note On entry, ctx must be empty, either freshly initialised
+ * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
+ * specific key type, check the result with mbedtls_pk_can_do().
+ *
+ * \note The key is also checked for correctness.
+ *
+ * \return 0 if successful, or a specific PK or PEM error code
+ */
+int mbedtls_pk_parse_key( mbedtls_pk_context *ctx,
+ const unsigned char *key, size_t keylen,
+ const unsigned char *pwd, size_t pwdlen );
+
+/** \ingroup pk_module */
+/**
+ * \brief Parse a public key in PEM or DER format
+ *
+ * \param ctx The PK context to fill. It must have been initialized
+ * but not set up.
+ * \param key Input buffer to parse.
+ * The buffer must contain the input exactly, with no
+ * extra trailing material. For PEM, the buffer must
+ * contain a null-terminated string.
+ * \param keylen Size of \b key in bytes.
+ * For PEM data, this includes the terminating null byte,
+ * so \p keylen must be equal to `strlen(key) + 1`.
+ *
+ * \note On entry, ctx must be empty, either freshly initialised
+ * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
+ * specific key type, check the result with mbedtls_pk_can_do().
+ *
+ * \note The key is also checked for correctness.
+ *
+ * \return 0 if successful, or a specific PK or PEM error code
+ */
+int mbedtls_pk_parse_public_key( mbedtls_pk_context *ctx,
+ const unsigned char *key, size_t keylen );
+
+#if defined(MBEDTLS_FS_IO)
+/** \ingroup pk_module */
+/**
+ * \brief Load and parse a private key
+ *
+ * \param ctx The PK context to fill. It must have been initialized
+ * but not set up.
+ * \param path filename to read the private key from
+ * \param password Optional password to decrypt the file.
+ * Pass \c NULL if expecting a non-encrypted key.
+ * Pass a null-terminated string if expecting an encrypted
+ * key; a non-encrypted key will also be accepted.
+ * The empty password is not supported.
+ *
+ * \note On entry, ctx must be empty, either freshly initialised
+ * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
+ * specific key type, check the result with mbedtls_pk_can_do().
+ *
+ * \note The key is also checked for correctness.
+ *
+ * \return 0 if successful, or a specific PK or PEM error code
+ */
+int mbedtls_pk_parse_keyfile( mbedtls_pk_context *ctx,
+ const char *path, const char *password );
+
+/** \ingroup pk_module */
+/**
+ * \brief Load and parse a public key
+ *
+ * \param ctx The PK context to fill. It must have been initialized
+ * but not set up.
+ * \param path filename to read the public key from
+ *
+ * \note On entry, ctx must be empty, either freshly initialised
+ * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If
+ * you need a specific key type, check the result with
+ * mbedtls_pk_can_do().
+ *
+ * \note The key is also checked for correctness.
+ *
+ * \return 0 if successful, or a specific PK or PEM error code
+ */
+int mbedtls_pk_parse_public_keyfile( mbedtls_pk_context *ctx, const char *path );
+#endif /* MBEDTLS_FS_IO */
+#endif /* MBEDTLS_PK_PARSE_C */
+
+#if defined(MBEDTLS_PK_WRITE_C)
+/**
+ * \brief Write a private key to a PKCS#1 or SEC1 DER structure
+ * Note: data is written at the end of the buffer! Use the
+ * return value to determine where you should start
+ * using the buffer
+ *
+ * \param ctx PK context which must contain a valid private key.
+ * \param buf buffer to write to
+ * \param size size of the buffer
+ *
+ * \return length of data written if successful, or a specific
+ * error code
+ */
+int mbedtls_pk_write_key_der( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
+
+/**
+ * \brief Write a public key to a SubjectPublicKeyInfo DER structure
+ * Note: data is written at the end of the buffer! Use the
+ * return value to determine where you should start
+ * using the buffer
+ *
+ * \param ctx PK context which must contain a valid public or private key.
+ * \param buf buffer to write to
+ * \param size size of the buffer
+ *
+ * \return length of data written if successful, or a specific
+ * error code
+ */
+int mbedtls_pk_write_pubkey_der( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
+
+#if defined(MBEDTLS_PEM_WRITE_C)
+/**
+ * \brief Write a public key to a PEM string
+ *
+ * \param ctx PK context which must contain a valid public or private key.
+ * \param buf Buffer to write to. The output includes a
+ * terminating null byte.
+ * \param size Size of the buffer in bytes.
+ *
+ * \return 0 if successful, or a specific error code
+ */
+int mbedtls_pk_write_pubkey_pem( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
+
+/**
+ * \brief Write a private key to a PKCS#1 or SEC1 PEM string
+ *
+ * \param ctx PK context which must contain a valid private key.
+ * \param buf Buffer to write to. The output includes a
+ * terminating null byte.
+ * \param size Size of the buffer in bytes.
+ *
+ * \return 0 if successful, or a specific error code
+ */
+int mbedtls_pk_write_key_pem( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
+#endif /* MBEDTLS_PEM_WRITE_C */
+#endif /* MBEDTLS_PK_WRITE_C */
+
+/*
+ * WARNING: Low-level functions. You probably do not want to use these unless
+ * you are certain you do ;)
+ */
+
+#if defined(MBEDTLS_PK_PARSE_C)
+/**
+ * \brief Parse a SubjectPublicKeyInfo DER structure
+ *
+ * \param p the position in the ASN.1 data
+ * \param end end of the buffer
+ * \param pk The PK context to fill. It must have been initialized
+ * but not set up.
+ *
+ * \return 0 if successful, or a specific PK error code
+ */
+int mbedtls_pk_parse_subpubkey( unsigned char **p, const unsigned char *end,
+ mbedtls_pk_context *pk );
+#endif /* MBEDTLS_PK_PARSE_C */
+
+#if defined(MBEDTLS_PK_WRITE_C)
+/**
+ * \brief Write a subjectPublicKey to ASN.1 data
+ * Note: function works backwards in data buffer
+ *
+ * \param p reference to current position pointer
+ * \param start start of the buffer (for bounds-checking)
+ * \param key PK context which must contain a valid public or private key.
+ *
+ * \return the length written or a negative error code
+ */
+int mbedtls_pk_write_pubkey( unsigned char **p, unsigned char *start,
+ const mbedtls_pk_context *key );
+#endif /* MBEDTLS_PK_WRITE_C */
+
+/*
+ * Internal module functions. You probably do not want to use these unless you
+ * know you do.
+ */
+#if defined(MBEDTLS_FS_IO)
+int mbedtls_pk_load_file( const char *path, unsigned char **buf, size_t *n );
+#endif
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+/**
+ * \brief Turn an EC key into an opaque one.
+ *
+ * \warning This is a temporary utility function for tests. It might
+ * change or be removed at any time without notice.
+ *
+ * \note Only ECDSA keys are supported so far. Signing with the
+ * specified hash is the only allowed use of that key.
+ *
+ * \param pk Input: the EC key to import to a PSA key.
+ * Output: a PK context wrapping that PSA key.
+ * \param key Output: a PSA key identifier.
+ * It's the caller's responsibility to call
+ * psa_destroy_key() on that key identifier after calling
+ * mbedtls_pk_free() on the PK context.
+ * \param hash_alg The hash algorithm to allow for use with that key.
+ *
+ * \return \c 0 if successful.
+ * \return An Mbed TLS error code otherwise.
+ */
+int mbedtls_pk_wrap_as_opaque( mbedtls_pk_context *pk,
+ psa_key_id_t *key,
+ psa_algorithm_t hash_alg );
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MBEDTLS_PK_H */