Add write_client_params

This commit is contained in:
Manuel Pégourié-Gonnard 2015-08-13 20:19:16 +02:00
parent ec0eece2ba
commit 614bd5e919
2 changed files with 80 additions and 0 deletions

View file

@ -177,6 +177,25 @@ int mbedtls_ecjpake_tls_read_server_params( mbedtls_ecjpake_context *ctx,
const unsigned char *buf,
size_t len );
/*
* \brief Generate and write ClientECJPAKEParams
* (the contents for the ClientKeyExchange)
*
* \param ctx Context to use
* \param buf Buffer to write the contents to
* \param len Buffer size
* \param olen Will be updated with the number of bytes written
* \param f_rng RNG function
* \param p_rng RNG parameter
*
* \return 0 if successfull,
* a negative error code otherwise
*/
int mbedtls_ecjpake_tls_write_client_params( mbedtls_ecjpake_context *ctx,
unsigned char *buf, size_t len, size_t *olen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );
/*
* \brief Read and process ClientECJPAKEParams
* (the contents for the ClientKeyExchange)

View file

@ -686,6 +686,62 @@ cleanup:
return( ret );
}
/*
* Generate and write ClientECJPAKEParams (7.4.2.6)
*/
int mbedtls_ecjpake_tls_write_client_params( mbedtls_ecjpake_context *ctx,
unsigned char *buf, size_t len, size_t *olen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret;
mbedtls_ecp_point GA, Xc;
mbedtls_mpi xc;
unsigned char *p = buf;
const unsigned char *end = buf + len;
size_t ec_len;
if( end < p )
return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
mbedtls_ecp_point_init( &GA );
mbedtls_ecp_point_init( &Xc );
mbedtls_mpi_init( &xc );
/*
* First generate private/public key pair (7.4.2.6.1)
*
* GA = X1 + X3 + X4
* xc = x2 * s mod n
* Xc = xc * GA
*/
MBEDTLS_MPI_CHK( ecjpake_ecp_add3( &ctx->grp, &GA,
&ctx->X1, &ctx->X3, &ctx->X4 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &xc, &ctx->xb, &ctx->s ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &xc, &xc, &ctx->grp.N ) );
MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &ctx->grp, &Xc, &xc, &GA, f_rng, p_rng ) );
/*
* Now write things out
*/
MBEDTLS_MPI_CHK( mbedtls_ecp_tls_write_point( &ctx->grp, &Xc,
MBEDTLS_ECP_PF_UNCOMPRESSED, &ec_len, p, end - p ) );
p += ec_len;
MBEDTLS_MPI_CHK( ecjpake_zkp_write( ctx->md_info, &ctx->grp,
&GA, &xc, &Xc, "client",
&p, end, f_rng, p_rng ) );
*olen = p - buf;
cleanup:
mbedtls_ecp_point_free( &GA );
mbedtls_ecp_point_free( &Xc );
mbedtls_mpi_free( &xc );
return( ret );
}
#if defined(MBEDTLS_SELF_TEST)
#if defined(MBEDTLS_PLATFORM_C)
@ -907,6 +963,11 @@ int mbedtls_ecjpake_self_test( int verbose )
TEST_ASSERT( mbedtls_ecjpake_tls_read_server_params( &cli, buf, len ) == 0 );
TEST_ASSERT( mbedtls_ecjpake_tls_write_client_params( &cli,
buf, sizeof( buf ), &len, ecjpake_lgc, NULL ) == 0 );
TEST_ASSERT( mbedtls_ecjpake_tls_read_client_params( &srv, buf, len ) == 0 );
if( verbose != 0 )
mbedtls_printf( "passed\n" );