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Add ecdsa_sign_det() with test vectors

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This commit is contained in:
Manuel Pégourié-Gonnard
2014-01-06 14:25:56 +01:00
parent 461d416892
commit 4daaef7e27
4 changed files with 305 additions and 14 deletions
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59
library/ecdsa.c
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@ -36,14 +36,6 @@
#include "polarssl/ecdsa.h"
#include "polarssl/asn1write.h"
#if defined(POLARSSL_ECDSA_DETERMINISTIC)
#include "polarssl/md.h"
#endif
/*
* If using deterministic ECDSA (RFC 6979), we need HMAC_DRBG.
* Actually a simplified version is enough, so we implement it below.
*/
#if defined(POLARSSL_ECDSA_DETERMINISTIC)
/*
* Simplified HMAC_DRBG context.
@ -63,10 +55,10 @@ typedef struct
* assumes personalisation is not null,
* assumes md_info is not NULL and valid.
*/
static int hmac_drbg_init( hmac_drbg_context *ctx,
const md_info_t * md_info,
const unsigned char *entropy, size_t entropy_len,
const unsigned char *pers, size_t pers_len )
static void hmac_drbg_init( hmac_drbg_context *ctx,
const md_info_t * md_info,
const unsigned char *entropy, size_t entropy_len,
const unsigned char *pers, size_t pers_len )
{
unsigned char sep[1];
size_t md_len = md_info->size;
@ -103,8 +95,6 @@ static int hmac_drbg_init( hmac_drbg_context *ctx,
md_hmac_starts( &ctx->md_ctx, ctx->K, md_len );
md_hmac_update( &ctx->md_ctx, ctx->V, md_len );
md_hmac_finish( &ctx->md_ctx, ctx->V );
return( 0 );
}
/*
@ -249,6 +239,47 @@ cleanup:
return( ret );
}
#if defined(POLARSSL_ECDSA_DETERMINISTIC)
/*
* Deterministic signature wrapper
*/
int ecdsa_sign_det( ecp_group *grp, mpi *r, mpi *s,
const mpi *d, const unsigned char *buf, size_t blen,
md_type_t md_alg )
{
int ret;
hmac_drbg_context rng_ctx;
unsigned char key[POLARSSL_ECP_MAX_BYTES];
unsigned char hash[POLARSSL_ECP_MAX_BYTES];
size_t grp_len = ( grp->nbits + 7 ) / 8;
const md_info_t *md_info;
mpi h;
if( ( md_info = md_info_from_type( md_alg ) ) == NULL )
return( POLARSSL_ERR_ECP_BAD_INPUT_DATA );
mpi_init( &h );
memset( &rng_ctx, 0, sizeof( hmac_drbg_context ) );
/* Export private key as entropy source */
MPI_CHK( mpi_write_binary( d, key, grp_len ) );
/* Export message hash as additional data; need to reduce it first */
MPI_CHK( derive_mpi( grp, &h, buf, blen ) );
MPI_CHK( mpi_write_binary( &h, hash, grp_len ) );
/* Initialize HMAC_DRBG and use it for signature */
hmac_drbg_init( &rng_ctx, md_info, key, grp_len, hash, grp_len );
ret = ecdsa_sign( grp, r, s, d, buf, blen,
hmac_drbg_random, &rng_ctx );
cleanup:
hmac_drbg_free( &rng_ctx );
mpi_free( &h );
return( ret );
}
#endif
/*
* Verify ECDSA signature of hashed message (SEC1 4.1.4)
* Obviously, compared to SEC1 4.1.3, we skip step 2 (hash message)