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Create functions for restartable sign

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This commit is contained in:
Manuel Pégourié-Gonnard 2017-04-21 12:54:46 +02:00
parent 5314f234ca
commit addb10efac
2 changed files with 83 additions and 10 deletions
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29
include/mbedtls/ecdsa.h
View file

@ -187,6 +187,35 @@ int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );
/**
* \brief Restartable version of \c mbedtls_ecdsa_write_signature()
*
* \note Performs the same job as \c mbedtls_ecdsa_write_signature()
* but can return early and restart according to the limit
* set with \c mbedtls_ecp_set_max_ops() to reduce blocking.
*
* \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
* \param rs_ctx Restart context
*
* \return See \c mbedtls_ecdsa_write_signature(), or
* MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of
* operations was reached: see \c mbedtls_ecp_set_max_ops().
*/
int mbedtls_ecdsa_write_signature_restartable( 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,
mbedtls_ecdsa_restart_ctx *rs_ctx );
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
#if ! defined(MBEDTLS_DEPRECATED_REMOVED)
#if defined(MBEDTLS_DEPRECATED_WARNING)

64
library/ecdsa.c
View file

@ -127,14 +127,18 @@ cleanup:
* Compute ECDSA signature of a hashed message (SEC1 4.1.3)
* Obviously, compared to SEC1 4.1.3, we skip step 4 (hash message)
*/
int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
static int ecdsa_sign_restartable( 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 )
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
mbedtls_ecdsa_restart_ctx *rs_ctx )
{
int ret, key_tries, sign_tries, blind_tries;
mbedtls_ecp_point R;
mbedtls_mpi k, e, t;
(void) rs_ctx; // temporary
/* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */
if( grp->N.p == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
@ -212,13 +216,26 @@ cleanup:
return( ret );
}
/*
* Compute ECDSA signature of a hashed message
*/
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 )
{
return( ecdsa_sign_restartable( grp, r, s, d, buf, blen,
f_rng, p_rng, NULL ) );
}
#if defined(MBEDTLS_ECDSA_DETERMINISTIC)
/*
* Deterministic signature wrapper
*/
int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
static int ecdsa_sign_det_restartable( 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 )
mbedtls_md_type_t md_alg,
mbedtls_ecdsa_restart_ctx *rs_ctx )
{
int ret;
mbedtls_hmac_drbg_context rng_ctx;
@ -227,6 +244,8 @@ int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi
const mbedtls_md_info_t *md_info;
mbedtls_mpi h;
(void) rs_ctx; // temporary
if( ( md_info = mbedtls_md_info_from_type( md_alg ) ) == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
@ -248,6 +267,16 @@ cleanup:
return( ret );
}
/*
* Deterministic signature wrapper
*/
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 )
{
return( ecdsa_sign_det_restartable( grp, r, s, d, buf, blen, md_alg, NULL ) );
}
#endif /* MBEDTLS_ECDSA_DETERMINISTIC */
/*
@ -427,11 +456,13 @@ static int ecdsa_signature_to_asn1( const mbedtls_mpi *r, const mbedtls_mpi *s,
/*
* Compute and write signature
*/
int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t md_alg,
int mbedtls_ecdsa_write_signature_restartable( 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 )
void *p_rng,
mbedtls_ecdsa_restart_ctx *rs_ctx )
{
int ret;
mbedtls_mpi r, s;
@ -443,13 +474,13 @@ int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx, mbedtls_md_type_t
(void) f_rng;
(void) p_rng;
MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign_det( &ctx->grp, &r, &s, &ctx->d,
hash, hlen, md_alg ) );
MBEDTLS_MPI_CHK( ecdsa_sign_det_restartable( &ctx->grp, &r, &s, &ctx->d,
hash, hlen, md_alg, rs_ctx ) );
#else
(void) md_alg;
MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign( &ctx->grp, &r, &s, &ctx->d,
hash, hlen, f_rng, p_rng ) );
MBEDTLS_MPI_CHK( ecdsa_sign_restartable( &ctx->grp, &r, &s, &ctx->d,
hash, hlen, f_rng, p_rng, rs_ctx ) );
#endif
MBEDTLS_MPI_CHK( ecdsa_signature_to_asn1( &r, &s, sig, slen ) );
@ -461,6 +492,19 @@ cleanup:
return( ret );
}
/*
* Compute and write signature
*/
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 )
{
return( mbedtls_ecdsa_write_signature_restartable(
ctx, md_alg, hash, hlen, sig, slen, f_rng, p_rng, NULL ) );
}
#if ! defined(MBEDTLS_DEPRECATED_REMOVED) && \
defined(MBEDTLS_ECDSA_DETERMINISTIC)
int mbedtls_ecdsa_write_signature_det( mbedtls_ecdsa_context *ctx,