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/**
* \file ecdsa.h
*
* \brief Elliptic curve DSA
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* 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.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#ifndef MBEDTLS_ECDSA_H
#define MBEDTLS_ECDSA_H
#include "ecp.h"
#include "md.h"
/*
* RFC 4492 page 20:
*
* Ecdsa-Sig-Value ::= SEQUENCE {
* r INTEGER,
* s INTEGER
* }
*
* Size is at most
* 1 (tag) + 1 (len) + 1 (initial 0) + ECP_MAX_BYTES for each of r and s,
* twice that + 1 (tag) + 2 (len) for the sequence
* (assuming ECP_MAX_BYTES is less than 126 for r and s,
* and less than 124 (total len <= 255) for the sequence)
*/
#if MBEDTLS_ECP_MAX_BYTES > 124
#error "MBEDTLS_ECP_MAX_BYTES bigger than expected, please fix MBEDTLS_ECDSA_MAX_LEN"
#endif
/** Maximum size of an ECDSA signature in bytes */
#define MBEDTLS_ECDSA_MAX_LEN ( 3 + 2 * ( 3 + MBEDTLS_ECP_MAX_BYTES ) )
/**
* \brief ECDSA context structure
*/
typedef mbedtls_ecp_keypair mbedtls_ecdsa_context;
#ifdef __cplusplus
extern "C" {
#endif
/**
* \brief Compute ECDSA signature of a previously hashed message
*
* \note The deterministic version is usually prefered.
*
* \param grp ECP group
* \param r First output integer
* \param s Second output integer
* \param d Private signing key
* \param buf Message hash
* \param blen Length of buf
* \param f_rng RNG function
* \param p_rng RNG parameter
*
* \note If the bitlength of the message hash is larger than the
* bitlength of the group order, then the hash is truncated as
* prescribed by SEC1 4.1.3 step 5.
*
* \return 0 if successful,
* or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
*/
int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
/**
* \brief Compute ECDSA signature of a previously hashed message,
* deterministic version (RFC 6979).
*
* \param grp ECP group
* \param r First output integer
* \param s Second output integer
* \param d Private signing key
* \param buf Message hash
* \param blen Length of buf
* \param md_alg MD algorithm used to hash the message
*
* \note If the bitlength of the message hash is larger than the
* bitlength of the group order, then the hash is truncated as
* prescribed by SEC1 4.1.3 step 5.
*
* \return 0 if successful,
* or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
*/
int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg );
#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
/**
* \brief Verify ECDSA signature of a previously hashed message
*
* \param grp ECP group
* \param buf Message hash
* \param blen Length of buf
* \param Q Public key to use for verification
* \param r First integer of the signature
* \param s Second integer of the signature
*
* \note If the bitlength of the message hash is larger than the
* bitlength of the group order, then the hash is truncated as
* prescribed by SEC1 4.1.4 step 3.
*
* \return 0 if successful,
* MBEDTLS_ERR_ECP_BAD_INPUT_DATA if signature is invalid
* or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
*/
int mbedtls_ecdsa_verify( mbedtls_ecp_group *grp,
const unsigned char *buf, size_t blen,
const mbedtls_ecp_point *Q, const mbedtls_mpi *r, const mbedtls_mpi *s);
/**
* \brief Compute ECDSA signature and write it to buffer,
* serialized as defined in RFC 4492 page 20.
* (Not thread-safe to use same context in multiple threads)
*
* \note The deterministic version (RFC 6979) is used if
* MBEDTLS_ECDSA_DETERMINISTIC is defined.
*
* \param ctx ECDSA context
* \param md_alg Algorithm that was used to hash the message
* \param hash Message hash
* \param hlen Length of hash
* \param sig Buffer that will hold the signature
* \param slen Length of the signature written
* \param f_rng RNG function
* \param p_rng RNG parameter
*
* \note The "sig" buffer must be at least as large as twice the
* size of the curve used, plus 9 (eg. 73 bytes if a 256-bit
* curve is used). MBEDTLS_ECDSA_MAX_LEN is always safe.
*
* \note If the bitlength of the message hash is larger than the
* bitlength of the group order, then the hash is truncated as
* prescribed by SEC1 4.1.3 step 5.
*
* \return 0 if successful,
* or a MBEDTLS_ERR_ECP_XXX, MBEDTLS_ERR_MPI_XXX or
* MBEDTLS_ERR_ASN1_XXX error code
*/
int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
#if ! defined(MBEDTLS_DEPRECATED_REMOVED)
#if defined(MBEDTLS_DEPRECATED_WARNING)
#define MBEDTLS_DEPRECATED __attribute__((deprecated))
#else
#define MBEDTLS_DEPRECATED
#endif
/**
* \brief Compute ECDSA signature and write it to buffer,
* serialized as defined in RFC 4492 page 20.
* Deterministic version, RFC 6979.
* (Not thread-safe to use same context in multiple threads)
*
* \deprecated Superseded by mbedtls_ecdsa_write_signature() in 2.0.0
*
* \param ctx ECDSA context
* \param hash Message hash
* \param hlen Length of hash
* \param sig Buffer that will hold the signature
* \param slen Length of the signature written
* \param md_alg MD algorithm used to hash the message
*
* \note The "sig" buffer must be at least as large as twice the
* size of the curve used, plus 9 (eg. 73 bytes if a 256-bit
* curve is used). MBEDTLS_ECDSA_MAX_LEN is always safe.
*
* \note If the bitlength of the message hash is larger than the
* bitlength of the group order, then the hash is truncated as
* prescribed by SEC1 4.1.3 step 5.
*
* \return 0 if successful,
* or a MBEDTLS_ERR_ECP_XXX, MBEDTLS_ERR_MPI_XXX or
* MBEDTLS_ERR_ASN1_XXX error code
*/
int mbedtls_ecdsa_write_signature_det( mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t *slen,
mbedtls_md_type_t md_alg ) MBEDTLS_DEPRECATED;
#undef MBEDTLS_DEPRECATED
#endif /* MBEDTLS_DEPRECATED_REMOVED */
#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
/**
* \brief Read and verify an ECDSA signature
*
* \param ctx ECDSA context
* \param hash Message hash
* \param hlen Size of hash
* \param sig Signature to read and verify
* \param slen Size of sig
*
* \note If the bitlength of the message hash is larger than the
* bitlength of the group order, then the hash is truncated as
* prescribed by SEC1 4.1.4 step 3.
*
* \return 0 if successful,
* MBEDTLS_ERR_ECP_BAD_INPUT_DATA if signature is invalid,
* MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH if the signature is
* valid but its actual length is less than siglen,
* or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_ERR_MPI_XXX error code
*/
int mbedtls_ecdsa_read_signature( mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
const unsigned char *sig, size_t slen );
/**
* \brief Generate an ECDSA keypair on the given curve
*
* \param ctx ECDSA context in which the keypair should be stored
* \param gid Group (elliptic curve) to use. One of the various
* MBEDTLS_ECP_DP_XXX macros depending on configuration.
* \param f_rng RNG function
* \param p_rng RNG parameter
*
* \return 0 on success, or a MBEDTLS_ERR_ECP_XXX code.
*/
int mbedtls_ecdsa_genkey( mbedtls_ecdsa_context *ctx, mbedtls_ecp_group_id gid,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
/**
* \brief Set an ECDSA context from an EC key pair
*
* \param ctx ECDSA context to set
* \param key EC key to use
*
* \return 0 on success, or a MBEDTLS_ERR_ECP_XXX code.
*/
int mbedtls_ecdsa_from_keypair( mbedtls_ecdsa_context *ctx, const mbedtls_ecp_keypair *key );
/**
* \brief Initialize context
*
* \param ctx Context to initialize
*/
void mbedtls_ecdsa_init( mbedtls_ecdsa_context *ctx );
/**
* \brief Free context
*
* \param ctx Context to free
*/
void mbedtls_ecdsa_free( mbedtls_ecdsa_context *ctx );
#ifdef __cplusplus
}
#endif
#endif /* ecdsa.h */
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