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/**
* \file ecdsa.h
*
* \brief Elliptic curve DSA
*
* Copyright (C) 2006-2013, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef POLARSSL_ECDSA_H
#define POLARSSL_ECDSA_H
#include "polarssl/ecp.h"
/**
* \brief ECDSA context structure
*
* \note Purposefully begins with the same members as struct ecp_keypair.
*/
typedef struct
{
ecp_group grp; /*!< ellipitic curve used */
mpi d; /*!< secret signature key */
ecp_point Q; /*!< public signature key */
mpi r; /*!< first integer from signature */
mpi s; /*!< second integer from signature */
}
ecdsa_context;
#ifdef __cplusplus
extern "C" {
#endif
/**
* \brief Compute ECDSA signature of a previously hashed message
*
* \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
*
* \return 0 if successful,
* or a POLARSSL_ERR_ECP_XXX or POLARSSL_MPI_XXX error code
*/
int ecdsa_sign( ecp_group *grp, mpi *r, mpi *s,
const mpi *d, const unsigned char *buf, size_t blen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
/**
* \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
*
* \return 0 if successful,
* POLARSSL_ERR_ECP_BAD_INPUT_DATA if signature is invalid
* or a POLARSSL_ERR_ECP_XXX or POLARSSL_MPI_XXX error code
*/
int ecdsa_verify( ecp_group *grp,
const unsigned char *buf, size_t blen,
const ecp_point *Q, const mpi *r, const mpi *s);
/**
* \brief Compute ECDSA signature and write it to buffer,
* serialized as defined in RFC 4492 page 20.
*
* \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 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 7 (eg. 71 bytes if a 256-bit
* curve is used).
*
* \return 0 if successful,
* or a POLARSSL_ERR_ECP, POLARSSL_ERR_MPI or
* POLARSSL_ERR_ASN1 error code
*/
int ecdsa_write_signature( ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );
/**
* \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
*
* \return 0 if successful,
* POLARSSL_ERR_ECP_BAD_INPUT_DATA if signature is invalid
* or a POLARSSL_ERR_ECP or POLARSSL_ERR_MPI error code
*/
int ecdsa_read_signature( 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
* POLARSSL_ECP_DP_XXX macros depending on configuration.
* \param f_rng RNG function
* \param p_rng RNG parameter
*
* \return 0 on success, or a POLARSSL_ERR_ECP code.
*/
int ecdsa_genkey( ecdsa_context *ctx, 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 POLARSSL_ERR_ECP code.
*/
int ecdsa_from_keypair( ecdsa_context *ctx, const ecp_keypair *key );
/**
* \brief Initialize context
*
* \param ctx Context to initialize
*/
void ecdsa_init( ecdsa_context *ctx );
/**
* \brief Free context
*
* \param ctx Context to free
*/
void ecdsa_free( ecdsa_context *ctx );
/**
* \brief Checkup routine
*
* \return 0 if successful, or 1 if the test failed
*/
int ecdsa_self_test( int verbose );
#ifdef __cplusplus
}
#endif
#endif