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, 1340 insertions, 0 deletions

diff --git a/lib/mbedtls-2.27.0/include/mbedtls/rsa.h b/lib/mbedtls-2.27.0/include/mbedtls/rsa.h
new file mode 100644
index 0000000..991026e
--- /dev/null
+++ b/lib/mbedtls-2.27.0/include/mbedtls/rsa.h
@@ -0,0 +1,1340 @@
+/**
+ * \file rsa.h
+ *
+ * \brief This file provides an API for the RSA public-key cryptosystem.
+ *
+ * The RSA public-key cryptosystem is defined in <em>Public-Key
+ * Cryptography Standards (PKCS) #1 v1.5: RSA Encryption</em>
+ * and <em>Public-Key Cryptography Standards (PKCS) #1 v2.1:
+ * RSA Cryptography Specifications</em>.
+ *
+ */
+/*
+ *  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_RSA_H
+#define MBEDTLS_RSA_H
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#include "mbedtls/bignum.h"
+#include "mbedtls/md.h"
+
+#if defined(MBEDTLS_THREADING_C)
+#include "mbedtls/threading.h"
+#endif
+
+/*
+ * RSA Error codes
+ */
+#define MBEDTLS_ERR_RSA_BAD_INPUT_DATA                    -0x4080  /**< Bad input parameters to function. */
+#define MBEDTLS_ERR_RSA_INVALID_PADDING                   -0x4100  /**< Input data contains invalid padding and is rejected. */
+#define MBEDTLS_ERR_RSA_KEY_GEN_FAILED                    -0x4180  /**< Something failed during generation of a key. */
+#define MBEDTLS_ERR_RSA_KEY_CHECK_FAILED                  -0x4200  /**< Key failed to pass the validity check of the library. */
+#define MBEDTLS_ERR_RSA_PUBLIC_FAILED                     -0x4280  /**< The public key operation failed. */
+#define MBEDTLS_ERR_RSA_PRIVATE_FAILED                    -0x4300  /**< The private key operation failed. */
+#define MBEDTLS_ERR_RSA_VERIFY_FAILED                     -0x4380  /**< The PKCS#1 verification failed. */
+#define MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE                  -0x4400  /**< The output buffer for decryption is not large enough. */
+#define MBEDTLS_ERR_RSA_RNG_FAILED                        -0x4480  /**< The random generator failed to generate non-zeros. */
+
+/* MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION is deprecated and should not be used.
+ */
+#define MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION             -0x4500  /**< The implementation does not offer the requested operation, for example, because of security violations or lack of functionality. */
+
+/* MBEDTLS_ERR_RSA_HW_ACCEL_FAILED is deprecated and should not be used. */
+#define MBEDTLS_ERR_RSA_HW_ACCEL_FAILED                   -0x4580  /**< RSA hardware accelerator failed. */
+
+/*
+ * RSA constants
+ */
+#define MBEDTLS_RSA_PUBLIC      0 /**< Request private key operation. */
+#define MBEDTLS_RSA_PRIVATE     1 /**< Request public key operation. */
+
+#define MBEDTLS_RSA_PKCS_V15    0 /**< Use PKCS#1 v1.5 encoding. */
+#define MBEDTLS_RSA_PKCS_V21    1 /**< Use PKCS#1 v2.1 encoding. */
+
+#define MBEDTLS_RSA_SIGN        1 /**< Identifier for RSA signature operations. */
+#define MBEDTLS_RSA_CRYPT       2 /**< Identifier for RSA encryption and decryption operations. */
+
+#define MBEDTLS_RSA_SALT_LEN_ANY    -1
+
+/*
+ * The above constants may be used even if the RSA module is compile out,
+ * eg for alternative (PKCS#11) RSA implemenations in the PK layers.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if !defined(MBEDTLS_RSA_ALT)
+// Regular implementation
+//
+
+/**
+ * \brief   The RSA context structure.
+ *
+ * \note    Direct manipulation of the members of this structure
+ *          is deprecated. All manipulation should instead be done through
+ *          the public interface functions.
+ */
+typedef struct mbedtls_rsa_context
+{
+    int ver;                    /*!<  Reserved for internal purposes.
+                                 *    Do not set this field in application
+                                 *    code. Its meaning might change without
+                                 *    notice. */
+    size_t len;                 /*!<  The size of \p N in Bytes. */
+
+    mbedtls_mpi N;              /*!<  The public modulus. */
+    mbedtls_mpi E;              /*!<  The public exponent. */
+
+    mbedtls_mpi D;              /*!<  The private exponent. */
+    mbedtls_mpi P;              /*!<  The first prime factor. */
+    mbedtls_mpi Q;              /*!<  The second prime factor. */
+
+    mbedtls_mpi DP;             /*!<  <code>D % (P - 1)</code>. */
+    mbedtls_mpi DQ;             /*!<  <code>D % (Q - 1)</code>. */
+    mbedtls_mpi QP;             /*!<  <code>1 / (Q % P)</code>. */
+
+    mbedtls_mpi RN;             /*!<  cached <code>R^2 mod N</code>. */
+
+    mbedtls_mpi RP;             /*!<  cached <code>R^2 mod P</code>. */
+    mbedtls_mpi RQ;             /*!<  cached <code>R^2 mod Q</code>. */
+
+    mbedtls_mpi Vi;             /*!<  The cached blinding value. */
+    mbedtls_mpi Vf;             /*!<  The cached un-blinding value. */
+
+    int padding;                /*!< Selects padding mode:
+                                     #MBEDTLS_RSA_PKCS_V15 for 1.5 padding and
+                                     #MBEDTLS_RSA_PKCS_V21 for OAEP or PSS. */
+    int hash_id;                /*!< Hash identifier of mbedtls_md_type_t type,
+                                     as specified in md.h for use in the MGF
+                                     mask generating function used in the
+                                     EME-OAEP and EMSA-PSS encodings. */
+#if defined(MBEDTLS_THREADING_C)
+    /* Invariant: the mutex is initialized iff ver != 0. */
+    mbedtls_threading_mutex_t mutex;    /*!<  Thread-safety mutex. */
+#endif
+}
+mbedtls_rsa_context;
+
+#else  /* MBEDTLS_RSA_ALT */
+#include "rsa_alt.h"
+#endif /* MBEDTLS_RSA_ALT */
+
+/**
+ * \brief          This function initializes an RSA context.
+ *
+ * \note           Set padding to #MBEDTLS_RSA_PKCS_V21 for the RSAES-OAEP
+ *                 encryption scheme and the RSASSA-PSS signature scheme.
+ *
+ * \note           The \p hash_id parameter is ignored when using
+ *                 #MBEDTLS_RSA_PKCS_V15 padding.
+ *
+ * \note           The choice of padding mode is strictly enforced for private key
+ *                 operations, since there might be security concerns in
+ *                 mixing padding modes. For public key operations it is
+ *                 a default value, which can be overridden by calling specific
+ *                 \c rsa_rsaes_xxx or \c rsa_rsassa_xxx functions.
+ *
+ * \note           The hash selected in \p hash_id is always used for OEAP
+ *                 encryption. For PSS signatures, it is always used for
+ *                 making signatures, but can be overridden for verifying them.
+ *                 If set to #MBEDTLS_MD_NONE, it is always overridden.
+ *
+ * \param ctx      The RSA context to initialize. This must not be \c NULL.
+ * \param padding  The padding mode to use. This must be either
+ *                 #MBEDTLS_RSA_PKCS_V15 or #MBEDTLS_RSA_PKCS_V21.
+ * \param hash_id  The hash identifier of ::mbedtls_md_type_t type, if
+ *                 \p padding is #MBEDTLS_RSA_PKCS_V21. It is unused
+ *                 otherwise.
+ */
+void mbedtls_rsa_init( mbedtls_rsa_context *ctx,
+                       int padding,
+                       int hash_id );
+
+/**
+ * \brief          This function imports a set of core parameters into an
+ *                 RSA context.
+ *
+ * \note           This function can be called multiple times for successive
+ *                 imports, if the parameters are not simultaneously present.
+ *
+ *                 Any sequence of calls to this function should be followed
+ *                 by a call to mbedtls_rsa_complete(), which checks and
+ *                 completes the provided information to a ready-for-use
+ *                 public or private RSA key.
+ *
+ * \note           See mbedtls_rsa_complete() for more information on which
+ *                 parameters are necessary to set up a private or public
+ *                 RSA key.
+ *
+ * \note           The imported parameters are copied and need not be preserved
+ *                 for the lifetime of the RSA context being set up.
+ *
+ * \param ctx      The initialized RSA context to store the parameters in.
+ * \param N        The RSA modulus. This may be \c NULL.
+ * \param P        The first prime factor of \p N. This may be \c NULL.
+ * \param Q        The second prime factor of \p N. This may be \c NULL.
+ * \param D        The private exponent. This may be \c NULL.
+ * \param E        The public exponent. This may be \c NULL.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_rsa_import( mbedtls_rsa_context *ctx,
+                        const mbedtls_mpi *N,
+                        const mbedtls_mpi *P, const mbedtls_mpi *Q,
+                        const mbedtls_mpi *D, const mbedtls_mpi *E );
+
+/**
+ * \brief          This function imports core RSA parameters, in raw big-endian
+ *                 binary format, into an RSA context.
+ *
+ * \note           This function can be called multiple times for successive
+ *                 imports, if the parameters are not simultaneously present.
+ *
+ *                 Any sequence of calls to this function should be followed
+ *                 by a call to mbedtls_rsa_complete(), which checks and
+ *                 completes the provided information to a ready-for-use
+ *                 public or private RSA key.
+ *
+ * \note           See mbedtls_rsa_complete() for more information on which
+ *                 parameters are necessary to set up a private or public
+ *                 RSA key.
+ *
+ * \note           The imported parameters are copied and need not be preserved
+ *                 for the lifetime of the RSA context being set up.
+ *
+ * \param ctx      The initialized RSA context to store the parameters in.
+ * \param N        The RSA modulus. This may be \c NULL.
+ * \param N_len    The Byte length of \p N; it is ignored if \p N == NULL.
+ * \param P        The first prime factor of \p N. This may be \c NULL.
+ * \param P_len    The Byte length of \p P; it ns ignored if \p P == NULL.
+ * \param Q        The second prime factor of \p N. This may be \c NULL.
+ * \param Q_len    The Byte length of \p Q; it is ignored if \p Q == NULL.
+ * \param D        The private exponent. This may be \c NULL.
+ * \param D_len    The Byte length of \p D; it is ignored if \p D == NULL.
+ * \param E        The public exponent. This may be \c NULL.
+ * \param E_len    The Byte length of \p E; it is ignored if \p E == NULL.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ */
+int mbedtls_rsa_import_raw( mbedtls_rsa_context *ctx,
+                            unsigned char const *N, size_t N_len,
+                            unsigned char const *P, size_t P_len,
+                            unsigned char const *Q, size_t Q_len,
+                            unsigned char const *D, size_t D_len,
+                            unsigned char const *E, size_t E_len );
+
+/**
+ * \brief          This function completes an RSA context from
+ *                 a set of imported core parameters.
+ *
+ *                 To setup an RSA public key, precisely \p N and \p E
+ *                 must have been imported.
+ *
+ *                 To setup an RSA private key, sufficient information must
+ *                 be present for the other parameters to be derivable.
+ *
+ *                 The default implementation supports the following:
+ *                 <ul><li>Derive \p P, \p Q from \p N, \p D, \p E.</li>
+ *                 <li>Derive \p N, \p D from \p P, \p Q, \p E.</li></ul>
+ *                 Alternative implementations need not support these.
+ *
+ *                 If this function runs successfully, it guarantees that
+ *                 the RSA context can be used for RSA operations without
+ *                 the risk of failure or crash.
+ *
+ * \warning        This function need not perform consistency checks
+ *                 for the imported parameters. In particular, parameters that
+ *                 are not needed by the implementation might be silently
+ *                 discarded and left unchecked. To check the consistency
+ *                 of the key material, see mbedtls_rsa_check_privkey().
+ *
+ * \param ctx      The initialized RSA context holding imported parameters.
+ *
+ * \return         \c 0 on success.
+ * \return         #MBEDTLS_ERR_RSA_BAD_INPUT_DATA if the attempted derivations
+ *                 failed.
+ *
+ */
+int mbedtls_rsa_complete( mbedtls_rsa_context *ctx );
+
+/**
+ * \brief          This function exports the core parameters of an RSA key.
+ *
+ *                 If this function runs successfully, the non-NULL buffers
+ *                 pointed to by \p N, \p P, \p Q, \p D, and \p E are fully
+ *                 written, with additional unused space filled leading by
+ *                 zero Bytes.
+ *
+ *                 Possible reasons for returning
+ *                 #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED:<ul>
+ *                 <li>An alternative RSA implementation is in use, which
+ *                 stores the key externally, and either cannot or should
+ *                 not export it into RAM.</li>
+ *                 <li>A SW or HW implementation might not support a certain
+ *                 deduction. For example, \p P, \p Q from \p N, \p D,
+ *                 and \p E if the former are not part of the
+ *                 implementation.</li></ul>
+ *
+ *                 If the function fails due to an unsupported operation,
+ *                 the RSA context stays intact and remains usable.
+ *
+ * \param ctx      The initialized RSA context.
+ * \param N        The MPI to hold the RSA modulus.
+ *                 This may be \c NULL if this field need not be exported.
+ * \param P        The MPI to hold the first prime factor of \p N.
+ *                 This may be \c NULL if this field need not be exported.
+ * \param Q        The MPI to hold the second prime factor of \p N.
+ *                 This may be \c NULL if this field need not be exported.
+ * \param D        The MPI to hold the private exponent.
+ *                 This may be \c NULL if this field need not be exported.
+ * \param E        The MPI to hold the public exponent.
+ *                 This may be \c NULL if this field need not be exported.
+ *
+ * \return         \c 0 on success.
+ * \return         #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED if exporting the
+ *                 requested parameters cannot be done due to missing
+ *                 functionality or because of security policies.
+ * \return         A non-zero return code on any other failure.
+ *
+ */
+int mbedtls_rsa_export( const mbedtls_rsa_context *ctx,
+                        mbedtls_mpi *N, mbedtls_mpi *P, mbedtls_mpi *Q,
+                        mbedtls_mpi *D, mbedtls_mpi *E );
+
+/**
+ * \brief          This function exports core parameters of an RSA key
+ *                 in raw big-endian binary format.
+ *
+ *                 If this function runs successfully, the non-NULL buffers
+ *                 pointed to by \p N, \p P, \p Q, \p D, and \p E are fully
+ *                 written, with additional unused space filled leading by
+ *                 zero Bytes.
+ *
+ *                 Possible reasons for returning
+ *                 #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED:<ul>
+ *                 <li>An alternative RSA implementation is in use, which
+ *                 stores the key externally, and either cannot or should
+ *                 not export it into RAM.</li>
+ *                 <li>A SW or HW implementation might not support a certain
+ *                 deduction. For example, \p P, \p Q from \p N, \p D,
+ *                 and \p E if the former are not part of the
+ *                 implementation.</li></ul>
+ *                 If the function fails due to an unsupported operation,
+ *                 the RSA context stays intact and remains usable.
+ *
+ * \note           The length parameters are ignored if the corresponding
+ *                 buffer pointers are NULL.
+ *
+ * \param ctx      The initialized RSA context.
+ * \param N        The Byte array to store the RSA modulus,
+ *                 or \c NULL if this field need not be exported.
+ * \param N_len    The size of the buffer for the modulus.
+ * \param P        The Byte array to hold the first prime factor of \p N,
+ *                 or \c NULL if this field need not be exported.
+ * \param P_len    The size of the buffer for the first prime factor.
+ * \param Q        The Byte array to hold the second prime factor of \p N,
+ *                 or \c NULL if this field need not be exported.
+ * \param Q_len    The size of the buffer for the second prime factor.
+ * \param D        The Byte array to hold the private exponent,
+ *                 or \c NULL if this field need not be exported.
+ * \param D_len    The size of the buffer for the private exponent.
+ * \param E        The Byte array to hold the public exponent,
+ *                 or \c NULL if this field need not be exported.
+ * \param E_len    The size of the buffer for the public exponent.
+ *
+ * \return         \c 0 on success.
+ * \return         #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED if exporting the
+ *                 requested parameters cannot be done due to missing
+ *                 functionality or because of security policies.
+ * \return         A non-zero return code on any other failure.
+ */
+int mbedtls_rsa_export_raw( const mbedtls_rsa_context *ctx,
+                            unsigned char *N, size_t N_len,
+                            unsigned char *P, size_t P_len,
+                            unsigned char *Q, size_t Q_len,
+                            unsigned char *D, size_t D_len,
+                            unsigned char *E, size_t E_len );
+
+/**
+ * \brief          This function exports CRT parameters of a private RSA key.
+ *
+ * \note           Alternative RSA implementations not using CRT-parameters
+ *                 internally can implement this function based on
+ *                 mbedtls_rsa_deduce_opt().
+ *
+ * \param ctx      The initialized RSA context.
+ * \param DP       The MPI to hold \c D modulo `P-1`,
+ *                 or \c NULL if it need not be exported.
+ * \param DQ       The MPI to hold \c D modulo `Q-1`,
+ *                 or \c NULL if it need not be exported.
+ * \param QP       The MPI to hold modular inverse of \c Q modulo \c P,
+ *                 or \c NULL if it need not be exported.
+ *
+ * \return         \c 0 on success.
+ * \return         A non-zero error code on failure.
+ *
+ */
+int mbedtls_rsa_export_crt( const mbedtls_rsa_context *ctx,
+                            mbedtls_mpi *DP, mbedtls_mpi *DQ, mbedtls_mpi *QP );
+
+/**
+ * \brief          This function sets padding for an already initialized RSA
+ *                 context. See mbedtls_rsa_init() for details.
+ *
+ * \param ctx      The initialized RSA context to be configured.
+ * \param padding  The padding mode to use. This must be either
+ *                 #MBEDTLS_RSA_PKCS_V15 or #MBEDTLS_RSA_PKCS_V21.
+ * \param hash_id  The #MBEDTLS_RSA_PKCS_V21 hash identifier.
+ */
+void mbedtls_rsa_set_padding( mbedtls_rsa_context *ctx, int padding,
+                              int hash_id );
+
+/**
+ * \brief          This function retrieves the length of RSA modulus in Bytes.
+ *
+ * \param ctx      The initialized RSA context.
+ *
+ * \return         The length of the RSA modulus in Bytes.
+ *
+ */
+size_t mbedtls_rsa_get_len( const mbedtls_rsa_context *ctx );
+
+/**
+ * \brief          This function generates an RSA keypair.
+ *
+ * \note           mbedtls_rsa_init() must be called before this function,
+ *                 to set up the RSA context.
+ *
+ * \param ctx      The initialized RSA context used to hold the key.
+ * \param f_rng    The RNG function to be used for key generation.
+ *                 This must not be \c NULL.
+ * \param p_rng    The RNG context to be passed to \p f_rng.
+ *                 This may be \c NULL if \p f_rng doesn't need a context.
+ * \param nbits    The size of the public key in bits.
+ * \param exponent The public exponent to use. For example, \c 65537.
+ *                 This must be odd and greater than \c 1.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
+                         int (*f_rng)(void *, unsigned char *, size_t),
+                         void *p_rng,
+                         unsigned int nbits, int exponent );
+
+/**
+ * \brief          This function checks if a context contains at least an RSA
+ *                 public key.
+ *
+ *                 If the function runs successfully, it is guaranteed that
+ *                 enough information is present to perform an RSA public key
+ *                 operation using mbedtls_rsa_public().
+ *
+ * \param ctx      The initialized RSA context to check.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ *
+ */
+int mbedtls_rsa_check_pubkey( const mbedtls_rsa_context *ctx );
+
+/**
+ * \brief      This function checks if a context contains an RSA private key
+ *             and perform basic consistency checks.
+ *
+ * \note       The consistency checks performed by this function not only
+ *             ensure that mbedtls_rsa_private() can be called successfully
+ *             on the given context, but that the various parameters are
+ *             mutually consistent with high probability, in the sense that
+ *             mbedtls_rsa_public() and mbedtls_rsa_private() are inverses.
+ *
+ * \warning    This function should catch accidental misconfigurations
+ *             like swapping of parameters, but it cannot establish full
+ *             trust in neither the quality nor the consistency of the key
+ *             material that was used to setup the given RSA context:
+ *             <ul><li>Consistency: Imported parameters that are irrelevant
+ *             for the implementation might be silently dropped. If dropped,
+ *             the current function does not have access to them,
+ *             and therefore cannot check them. See mbedtls_rsa_complete().
+ *             If you want to check the consistency of the entire
+ *             content of an PKCS1-encoded RSA private key, for example, you
+ *             should use mbedtls_rsa_validate_params() before setting
+ *             up the RSA context.
+ *             Additionally, if the implementation performs empirical checks,
+ *             these checks substantiate but do not guarantee consistency.</li>
+ *             <li>Quality: This function is not expected to perform
+ *             extended quality assessments like checking that the prime
+ *             factors are safe. Additionally, it is the responsibility of the
+ *             user to ensure the trustworthiness of the source of his RSA
+ *             parameters, which goes beyond what is effectively checkable
+ *             by the library.</li></ul>
+ *
+ * \param ctx  The initialized RSA context to check.
+ *
+ * \return     \c 0 on success.
+ * \return     An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_check_privkey( const mbedtls_rsa_context *ctx );
+
+/**
+ * \brief          This function checks a public-private RSA key pair.
+ *
+ *                 It checks each of the contexts, and makes sure they match.
+ *
+ * \param pub      The initialized RSA context holding the public key.
+ * \param prv      The initialized RSA context holding the private key.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_check_pub_priv( const mbedtls_rsa_context *pub,
+                                const mbedtls_rsa_context *prv );
+
+/**
+ * \brief          This function performs an RSA public key operation.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param input    The input buffer. This must be a readable buffer
+ *                 of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ * \param output   The output buffer. This must be a writable buffer
+ *                 of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ *
+ * \note           This function does not handle message padding.
+ *
+ * \note           Make sure to set \p input[0] = 0 or ensure that
+ *                 input is smaller than \p N.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_public( mbedtls_rsa_context *ctx,
+                const unsigned char *input,
+                unsigned char *output );
+
+/**
+ * \brief          This function performs an RSA private key operation.
+ *
+ * \note           Blinding is used if and only if a PRNG is provided.
+ *
+ * \note           If blinding is used, both the base of exponentation
+ *                 and the exponent are blinded, providing protection
+ *                 against some side-channel attacks.
+ *
+ * \warning        It is deprecated and a security risk to not provide
+ *                 a PRNG here and thereby prevent the use of blinding.
+ *                 Future versions of the library may enforce the presence
+ *                 of a PRNG.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function, used for blinding. It is discouraged
+ *                 and deprecated to pass \c NULL here, in which case
+ *                 blinding will be omitted.
+ * \param p_rng    The RNG context to pass to \p f_rng. This may be \c NULL
+ *                 if \p f_rng is \c NULL or if \p f_rng doesn't need a context.
+ * \param input    The input buffer. This must be a readable buffer
+ *                 of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ * \param output   The output buffer. This must be a writable buffer
+ *                 of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ *
+ */
+int mbedtls_rsa_private( mbedtls_rsa_context *ctx,
+                 int (*f_rng)(void *, unsigned char *, size_t),
+                 void *p_rng,
+                 const unsigned char *input,
+                 unsigned char *output );
+
+/**
+ * \brief          This function adds the message padding, then performs an RSA
+ *                 operation.
+ *
+ *                 It is the generic wrapper for performing a PKCS#1 encryption
+ *                 operation using the \p mode from the context.
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PRIVATE mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PUBLIC.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PRIVATE and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG to use. It is mandatory for PKCS#1 v2.1 padding
+ *                 encoding, and for PKCS#1 v1.5 padding encoding when used
+ *                 with \p mode set to #MBEDTLS_RSA_PUBLIC. For PKCS#1 v1.5
+ *                 padding encoding and \p mode set to #MBEDTLS_RSA_PRIVATE,
+ *                 it is used for blinding and should be provided in this
+ *                 case; see mbedtls_rsa_private() for more.
+ * \param p_rng    The RNG context to be passed to \p f_rng. May be
+ *                 \c NULL if \p f_rng is \c NULL or if \p f_rng doesn't
+ *                 need a context argument.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PUBLIC or #MBEDTLS_RSA_PRIVATE (deprecated).
+ * \param ilen     The length of the plaintext in Bytes.
+ * \param input    The input data to encrypt. This must be a readable
+ *                 buffer of size \p ilen Bytes. It may be \c NULL if
+ *                 `ilen == 0`.
+ * \param output   The output buffer. This must be a writable buffer
+ *                 of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_pkcs1_encrypt( mbedtls_rsa_context *ctx,
+                       int (*f_rng)(void *, unsigned char *, size_t),
+                       void *p_rng,
+                       int mode, size_t ilen,
+                       const unsigned char *input,
+                       unsigned char *output );
+
+/**
+ * \brief          This function performs a PKCS#1 v1.5 encryption operation
+ *                 (RSAES-PKCS1-v1_5-ENCRYPT).
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PRIVATE mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PUBLIC.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PRIVATE and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function to use. It is needed for padding generation
+ *                 if \p mode is #MBEDTLS_RSA_PUBLIC. If \p mode is
+ *                 #MBEDTLS_RSA_PRIVATE (discouraged), it is used for
+ *                 blinding and should be provided; see mbedtls_rsa_private().
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may
+ *                 be \c NULL if \p f_rng is \c NULL or if \p f_rng
+ *                 doesn't need a context argument.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PUBLIC or #MBEDTLS_RSA_PRIVATE (deprecated).
+ * \param ilen     The length of the plaintext in Bytes.
+ * \param input    The input data to encrypt. This must be a readable
+ *                 buffer of size \p ilen Bytes. It may be \c NULL if
+ *                 `ilen == 0`.
+ * \param output   The output buffer. This must be a writable buffer
+ *                 of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsaes_pkcs1_v15_encrypt( mbedtls_rsa_context *ctx,
+                                 int (*f_rng)(void *, unsigned char *, size_t),
+                                 void *p_rng,
+                                 int mode, size_t ilen,
+                                 const unsigned char *input,
+                                 unsigned char *output );
+
+/**
+ * \brief            This function performs a PKCS#1 v2.1 OAEP encryption
+ *                   operation (RSAES-OAEP-ENCRYPT).
+ *
+ * \note             The output buffer must be as large as the size
+ *                   of ctx->N. For example, 128 Bytes if RSA-1024 is used.
+ *
+ * \deprecated       It is deprecated and discouraged to call this function
+ *                   in #MBEDTLS_RSA_PRIVATE mode. Future versions of the library
+ *                   are likely to remove the \p mode argument and have it
+ *                   implicitly set to #MBEDTLS_RSA_PUBLIC.
+ *
+ * \note             Alternative implementations of RSA need not support
+ *                   mode being set to #MBEDTLS_RSA_PRIVATE and might instead
+ *                   return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx        The initnialized RSA context to use.
+ * \param f_rng      The RNG function to use. This is needed for padding
+ *                   generation and must be provided.
+ * \param p_rng      The RNG context to be passed to \p f_rng. This may
+ *                   be \c NULL if \p f_rng doesn't need a context argument.
+ * \param mode       The mode of operation. This must be either
+ *                   #MBEDTLS_RSA_PUBLIC or #MBEDTLS_RSA_PRIVATE (deprecated).
+ * \param label      The buffer holding the custom label to use.
+ *                   This must be a readable buffer of length \p label_len
+ *                   Bytes. It may be \c NULL if \p label_len is \c 0.
+ * \param label_len  The length of the label in Bytes.
+ * \param ilen       The length of the plaintext buffer \p input in Bytes.
+ * \param input      The input data to encrypt. This must be a readable
+ *                   buffer of size \p ilen Bytes. It may be \c NULL if
+ *                   `ilen == 0`.
+ * \param output     The output buffer. This must be a writable buffer
+ *                   of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                   for an 2048-bit RSA modulus.
+ *
+ * \return           \c 0 on success.
+ * \return           An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsaes_oaep_encrypt( mbedtls_rsa_context *ctx,
+                            int (*f_rng)(void *, unsigned char *, size_t),
+                            void *p_rng,
+                            int mode,
+                            const unsigned char *label, size_t label_len,
+                            size_t ilen,
+                            const unsigned char *input,
+                            unsigned char *output );
+
+/**
+ * \brief          This function performs an RSA operation, then removes the
+ *                 message padding.
+ *
+ *                 It is the generic wrapper for performing a PKCS#1 decryption
+ *                 operation using the \p mode from the context.
+ *
+ * \note           The output buffer length \c output_max_len should be
+ *                 as large as the size \p ctx->len of \p ctx->N (for example,
+ *                 128 Bytes if RSA-1024 is used) to be able to hold an
+ *                 arbitrary decrypted message. If it is not large enough to
+ *                 hold the decryption of the particular ciphertext provided,
+ *                 the function returns \c MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PUBLIC mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PRIVATE.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PUBLIC and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function. If \p mode is #MBEDTLS_RSA_PRIVATE,
+ *                 this is used for blinding and should be provided; see
+ *                 mbedtls_rsa_private() for more. If \p mode is
+ *                 #MBEDTLS_RSA_PUBLIC, it is ignored.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be
+ *                 \c NULL if \p f_rng is \c NULL or doesn't need a context.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PRIVATE or #MBEDTLS_RSA_PUBLIC (deprecated).
+ * \param olen     The address at which to store the length of
+ *                 the plaintext. This must not be \c NULL.
+ * \param input    The ciphertext buffer. This must be a readable buffer
+ *                 of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ * \param output   The buffer used to hold the plaintext. This must
+ *                 be a writable buffer of length \p output_max_len Bytes.
+ * \param output_max_len The length in Bytes of the output buffer \p output.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_pkcs1_decrypt( mbedtls_rsa_context *ctx,
+                       int (*f_rng)(void *, unsigned char *, size_t),
+                       void *p_rng,
+                       int mode, size_t *olen,
+                       const unsigned char *input,
+                       unsigned char *output,
+                       size_t output_max_len );
+
+/**
+ * \brief          This function performs a PKCS#1 v1.5 decryption
+ *                 operation (RSAES-PKCS1-v1_5-DECRYPT).
+ *
+ * \note           The output buffer length \c output_max_len should be
+ *                 as large as the size \p ctx->len of \p ctx->N, for example,
+ *                 128 Bytes if RSA-1024 is used, to be able to hold an
+ *                 arbitrary decrypted message. If it is not large enough to
+ *                 hold the decryption of the particular ciphertext provided,
+ *                 the function returns #MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PUBLIC mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PRIVATE.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PUBLIC and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function. If \p mode is #MBEDTLS_RSA_PRIVATE,
+ *                 this is used for blinding and should be provided; see
+ *                 mbedtls_rsa_private() for more. If \p mode is
+ *                 #MBEDTLS_RSA_PUBLIC, it is ignored.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be
+ *                 \c NULL if \p f_rng is \c NULL or doesn't need a context.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PRIVATE or #MBEDTLS_RSA_PUBLIC (deprecated).
+ * \param olen     The address at which to store the length of
+ *                 the plaintext. This must not be \c NULL.
+ * \param input    The ciphertext buffer. This must be a readable buffer
+ *                 of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ * \param output   The buffer used to hold the plaintext. This must
+ *                 be a writable buffer of length \p output_max_len Bytes.
+ * \param output_max_len The length in Bytes of the output buffer \p output.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ *
+ */
+int mbedtls_rsa_rsaes_pkcs1_v15_decrypt( mbedtls_rsa_context *ctx,
+                                 int (*f_rng)(void *, unsigned char *, size_t),
+                                 void *p_rng,
+                                 int mode, size_t *olen,
+                                 const unsigned char *input,
+                                 unsigned char *output,
+                                 size_t output_max_len );
+
+/**
+ * \brief            This function performs a PKCS#1 v2.1 OAEP decryption
+ *                   operation (RSAES-OAEP-DECRYPT).
+ *
+ * \note             The output buffer length \c output_max_len should be
+ *                   as large as the size \p ctx->len of \p ctx->N, for
+ *                   example, 128 Bytes if RSA-1024 is used, to be able to
+ *                   hold an arbitrary decrypted message. If it is not
+ *                   large enough to hold the decryption of the particular
+ *                   ciphertext provided, the function returns
+ *                   #MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.
+ *
+ * \deprecated       It is deprecated and discouraged to call this function
+ *                   in #MBEDTLS_RSA_PUBLIC mode. Future versions of the library
+ *                   are likely to remove the \p mode argument and have it
+ *                   implicitly set to #MBEDTLS_RSA_PRIVATE.
+ *
+ * \note             Alternative implementations of RSA need not support
+ *                   mode being set to #MBEDTLS_RSA_PUBLIC and might instead
+ *                   return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx        The initialized RSA context to use.
+ * \param f_rng      The RNG function. If \p mode is #MBEDTLS_RSA_PRIVATE,
+ *                   this is used for blinding and should be provided; see
+ *                   mbedtls_rsa_private() for more. If \p mode is
+ *                   #MBEDTLS_RSA_PUBLIC, it is ignored.
+ * \param p_rng      The RNG context to be passed to \p f_rng. This may be
+ *                   \c NULL if \p f_rng is \c NULL or doesn't need a context.
+ * \param mode       The mode of operation. This must be either
+ *                   #MBEDTLS_RSA_PRIVATE or #MBEDTLS_RSA_PUBLIC (deprecated).
+ * \param label      The buffer holding the custom label to use.
+ *                   This must be a readable buffer of length \p label_len
+ *                   Bytes. It may be \c NULL if \p label_len is \c 0.
+ * \param label_len  The length of the label in Bytes.
+ * \param olen       The address at which to store the length of
+ *                   the plaintext. This must not be \c NULL.
+ * \param input      The ciphertext buffer. This must be a readable buffer
+ *                   of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                   for an 2048-bit RSA modulus.
+ * \param output     The buffer used to hold the plaintext. This must
+ *                   be a writable buffer of length \p output_max_len Bytes.
+ * \param output_max_len The length in Bytes of the output buffer \p output.
+ *
+ * \return         \c 0 on success.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
+                            int (*f_rng)(void *, unsigned char *, size_t),
+                            void *p_rng,
+                            int mode,
+                            const unsigned char *label, size_t label_len,
+                            size_t *olen,
+                            const unsigned char *input,
+                            unsigned char *output,
+                            size_t output_max_len );
+
+/**
+ * \brief          This function performs a private RSA operation to sign
+ *                 a message digest using PKCS#1.
+ *
+ *                 It is the generic wrapper for performing a PKCS#1
+ *                 signature using the \p mode from the context.
+ *
+ * \note           The \p sig buffer must be as large as the size
+ *                 of \p ctx->N. For example, 128 Bytes if RSA-1024 is used.
+ *
+ * \note           For PKCS#1 v2.1 encoding, see comments on
+ *                 mbedtls_rsa_rsassa_pss_sign() for details on
+ *                 \p md_alg and \p hash_id.
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PUBLIC mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PRIVATE.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PUBLIC and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function to use. If the padding mode is PKCS#1 v2.1,
+ *                 this must be provided. If the padding mode is PKCS#1 v1.5 and
+ *                 \p mode is #MBEDTLS_RSA_PRIVATE, it is used for blinding
+ *                 and should be provided; see mbedtls_rsa_private() for more
+ *                 more. It is ignored otherwise.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be \c NULL
+ *                 if \p f_rng is \c NULL or doesn't need a context argument.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PRIVATE or #MBEDTLS_RSA_PUBLIC (deprecated).
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 Ths is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
+ * \param sig      The buffer to hold the signature. This must be a writable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus. A buffer length of
+ *                 #MBEDTLS_MPI_MAX_SIZE is always safe.
+ *
+ * \return         \c 0 if the signing operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_pkcs1_sign( mbedtls_rsa_context *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 );
+
+/**
+ * \brief          This function performs a PKCS#1 v1.5 signature
+ *                 operation (RSASSA-PKCS1-v1_5-SIGN).
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PUBLIC mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PRIVATE.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PUBLIC and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function. If \p mode is #MBEDTLS_RSA_PRIVATE,
+ *                 this is used for blinding and should be provided; see
+ *                 mbedtls_rsa_private() for more. If \p mode is
+ *                 #MBEDTLS_RSA_PUBLIC, it is ignored.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be \c NULL
+ *                 if \p f_rng is \c NULL or doesn't need a context argument.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PRIVATE or #MBEDTLS_RSA_PUBLIC (deprecated).
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 Ths is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
+ * \param sig      The buffer to hold the signature. This must be a writable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus. A buffer length of
+ *                 #MBEDTLS_MPI_MAX_SIZE is always safe.
+ *
+ * \return         \c 0 if the signing operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsassa_pkcs1_v15_sign( mbedtls_rsa_context *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 );
+
+/**
+ * \brief          This function performs a PKCS#1 v2.1 PSS signature
+ *                 operation (RSASSA-PSS-SIGN).
+ *
+ * \note           The \c hash_id set in \p ctx (when calling
+ *                 mbedtls_rsa_init() or by calling mbedtls_rsa_set_padding()
+ *                 afterwards) selects the hash used for the
+ *                 encoding operation and for the mask generation function
+ *                 (MGF1). For more details on the encoding operation and the
+ *                 mask generation function, consult <em>RFC-3447: Public-Key
+ *                 Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography
+ *                 Specifications</em>.
+ *
+ * \note           This function enforces that the provided salt length complies
+ *                 with FIPS 186-4 §5.5 (e) and RFC 8017 (PKCS#1 v2.2) §9.1.1
+ *                 step 3. The constraint is that the hash length plus the salt
+ *                 length plus 2 bytes must be at most the key length. If this
+ *                 constraint is not met, this function returns
+ *                 #MBEDTLS_ERR_RSA_BAD_INPUT_DATA.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function. It must not be \c NULL.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be \c NULL
+ *                 if \p f_rng doesn't need a context argument.
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 Ths is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
+ * \param saltlen  The length of the salt that should be used.
+ *                 If passed #MBEDTLS_RSA_SALT_LEN_ANY, the function will use
+ *                 the largest possible salt length up to the hash length,
+ *                 which is the largest permitted by some standards including
+ *                 FIPS 186-4 §5.5.
+ * \param sig      The buffer to hold the signature. This must be a writable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus. A buffer length of
+ *                 #MBEDTLS_MPI_MAX_SIZE is always safe.
+ *
+ * \return         \c 0 if the signing operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsassa_pss_sign_ext( mbedtls_rsa_context *ctx,
+                         int (*f_rng)(void *, unsigned char *, size_t),
+                         void *p_rng,
+                         mbedtls_md_type_t md_alg,
+                         unsigned int hashlen,
+                         const unsigned char *hash,
+                         int saltlen,
+                         unsigned char *sig );
+
+/**
+ * \brief          This function performs a PKCS#1 v2.1 PSS signature
+ *                 operation (RSASSA-PSS-SIGN).
+ *
+ * \note           The \c hash_id set in \p ctx (when calling
+ *                 mbedtls_rsa_init() or by calling mbedtls_rsa_set_padding()
+ *                 afterwards) selects the hash used for the
+ *                 encoding operation and for the mask generation function
+ *                 (MGF1). For more details on the encoding operation and the
+ *                 mask generation function, consult <em>RFC-3447: Public-Key
+ *                 Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography
+ *                 Specifications</em>.
+ *
+ * \note           This function always uses the maximum possible salt size,
+ *                 up to the length of the payload hash. This choice of salt
+ *                 size complies with FIPS 186-4 §5.5 (e) and RFC 8017 (PKCS#1
+ *                 v2.2) §9.1.1 step 3. Furthermore this function enforces a
+ *                 minimum salt size which is the hash size minus 2 bytes. If
+ *                 this minimum size is too large given the key size (the salt
+ *                 size, plus the hash size, plus 2 bytes must be no more than
+ *                 the key size in bytes), this function returns
+ *                 #MBEDTLS_ERR_RSA_BAD_INPUT_DATA.
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PUBLIC mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PRIVATE.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PUBLIC and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function. It must not be \c NULL.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be \c NULL
+ *                 if \p f_rng doesn't need a context argument.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PRIVATE or #MBEDTLS_RSA_PUBLIC (deprecated).
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
+ * \param sig      The buffer to hold the signature. This must be a writable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus. A buffer length of
+ *                 #MBEDTLS_MPI_MAX_SIZE is always safe.
+ *
+ * \return         \c 0 if the signing operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsassa_pss_sign( mbedtls_rsa_context *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 );
+
+/**
+ * \brief          This function performs a public RSA operation and checks
+ *                 the message digest.
+ *
+ *                 This is the generic wrapper for performing a PKCS#1
+ *                 verification using the mode from the context.
+ *
+ * \note           For PKCS#1 v2.1 encoding, see comments on
+ *                 mbedtls_rsa_rsassa_pss_verify() about \p md_alg and
+ *                 \p hash_id.
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PRIVATE mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 set to #MBEDTLS_RSA_PUBLIC.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PRIVATE and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA public key context to use.
+ * \param f_rng    The RNG function to use. If \p mode is #MBEDTLS_RSA_PRIVATE,
+ *                 this is used for blinding and should be provided; see
+ *                 mbedtls_rsa_private() for more. Otherwise, it is ignored.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be
+ *                 \c NULL if \p f_rng is \c NULL or doesn't need a context.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PUBLIC or #MBEDTLS_RSA_PRIVATE (deprecated).
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
+ * \param sig      The buffer holding the signature. This must be a readable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ *
+ * \return         \c 0 if the verify operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_pkcs1_verify( mbedtls_rsa_context *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,
+                      const unsigned char *sig );
+
+/**
+ * \brief          This function performs a PKCS#1 v1.5 verification
+ *                 operation (RSASSA-PKCS1-v1_5-VERIFY).
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PRIVATE mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 set to #MBEDTLS_RSA_PUBLIC.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PRIVATE and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA public key context to use.
+ * \param f_rng    The RNG function to use. If \p mode is #MBEDTLS_RSA_PRIVATE,
+ *                 this is used for blinding and should be provided; see
+ *                 mbedtls_rsa_private() for more. Otherwise, it is ignored.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be
+ *                 \c NULL if \p f_rng is \c NULL or doesn't need a context.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PUBLIC or #MBEDTLS_RSA_PRIVATE (deprecated).
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
+ * \param sig      The buffer holding the signature. This must be a readable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ *
+ * \return         \c 0 if the verify operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsassa_pkcs1_v15_verify( mbedtls_rsa_context *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,
+                                 const unsigned char *sig );
+
+/**
+ * \brief          This function performs a PKCS#1 v2.1 PSS verification
+ *                 operation (RSASSA-PSS-VERIFY).
+ *
+ * \note           The \c hash_id set in \p ctx (when calling
+ *                 mbedtls_rsa_init() or by calling mbedtls_rsa_set_padding()
+ *                 afterwards) selects the hash used for the
+ *                 encoding operation and for the mask generation function
+ *                 (MGF1). For more details on the encoding operation and the
+ *                 mask generation function, consult <em>RFC-3447: Public-Key
+ *                 Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography
+ *                 Specifications</em>. If the \c hash_id set in \p ctx is
+ *                 #MBEDTLS_MD_NONE, the \p md_alg parameter is used.
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PRIVATE mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PUBLIC.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PRIVATE and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA public key context to use.
+ * \param f_rng    The RNG function to use. If \p mode is #MBEDTLS_RSA_PRIVATE,
+ *                 this is used for blinding and should be provided; see
+ *                 mbedtls_rsa_private() for more. Otherwise, it is ignored.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be
+ *                 \c NULL if \p f_rng is \c NULL or doesn't need a context.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PUBLIC or #MBEDTLS_RSA_PRIVATE (deprecated).
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
+ * \param sig      The buffer holding the signature. This must be a readable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ *
+ * \return         \c 0 if the verify operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsassa_pss_verify( mbedtls_rsa_context *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,
+                           const unsigned char *sig );
+
+/**
+ * \brief          This function performs a PKCS#1 v2.1 PSS verification
+ *                 operation (RSASSA-PSS-VERIFY).
+ *
+ * \note           The \p sig buffer must be as large as the size
+ *                 of \p ctx->N. For example, 128 Bytes if RSA-1024 is used.
+ *
+ * \note           The \c hash_id set in \p ctx (when calling
+ *                 mbedtls_rsa_init() or by calling mbedtls_rsa_set_padding()
+ *                 afterwards) is ignored.
+ *
+ * \param ctx      The initialized RSA public key context to use.
+ * \param f_rng    The RNG function to use. If \p mode is #MBEDTLS_RSA_PRIVATE,
+ *                 this is used for blinding and should be provided; see
+ *                 mbedtls_rsa_private() for more. Otherwise, it is ignored.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be
+ *                 \c NULL if \p f_rng is \c NULL or doesn't need a context.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PUBLIC or #MBEDTLS_RSA_PRIVATE.
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
+ * \param mgf1_hash_id      The message digest algorithm used for the
+ *                          verification operation and the mask generation
+ *                          function (MGF1). For more details on the encoding
+ *                          operation and the mask generation function, consult
+ *                          <em>RFC-3447: Public-Key Cryptography Standards
+ *                          (PKCS) #1 v2.1: RSA Cryptography
+ *                          Specifications</em>.
+ * \param expected_salt_len The length of the salt used in padding. Use
+ *                          #MBEDTLS_RSA_SALT_LEN_ANY to accept any salt length.
+ * \param sig      The buffer holding the signature. This must be a readable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus.
+ *
+ * \return         \c 0 if the verify operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsassa_pss_verify_ext( mbedtls_rsa_context *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,
+                               mbedtls_md_type_t mgf1_hash_id,
+                               int expected_salt_len,
+                               const unsigned char *sig );
+
+/**
+ * \brief          This function copies the components of an RSA context.
+ *
+ * \param dst      The destination context. This must be initialized.
+ * \param src      The source context. This must be initialized.
+ *
+ * \return         \c 0 on success.
+ * \return         #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory allocation failure.
+ */
+int mbedtls_rsa_copy( mbedtls_rsa_context *dst, const mbedtls_rsa_context *src );
+
+/**
+ * \brief          This function frees the components of an RSA key.
+ *
+ * \param ctx      The RSA context to free. May be \c NULL, in which case
+ *                 this function is a no-op. If it is not \c NULL, it must
+ *                 point to an initialized RSA context.
+ */
+void mbedtls_rsa_free( mbedtls_rsa_context *ctx );
+
+#if defined(MBEDTLS_SELF_TEST)
+
+/**
+ * \brief          The RSA checkup routine.
+ *
+ * \return         \c 0 on success.
+ * \return         \c 1 on failure.
+ */
+int mbedtls_rsa_self_test( int verbose );
+
+#endif /* MBEDTLS_SELF_TEST */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* rsa.h */