* GECC = Guide to Elliptic Curve Cryptography - Hankerson, Menezes, Vanstone
* FIPS 186-3 http://csrc.nist.gov/publications/fips/fips186-3/fips_186-3.pdf
* RFC 4492 for the related TLS structures and constants
+ * RFC 7748 for the Curve448 and Curve25519 curve definitions
*
* [Curve25519] http://cr.yp.to/ecdh/curve25519-20060209.pdf
*
#include MBEDTLS_CONFIG_FILE
#endif
+/**
+ * \brief Function level alternative implementation.
+ *
+ * The MBEDTLS_ECP_INTERNAL_ALT macro enables alternative implementations to
+ * replace certain functions in this module. The alternative implementations are
+ * typically hardware accelerators and need to activate the hardware before the
+ * computation starts and deactivate it after it finishes. The
+ * mbedtls_internal_ecp_init() and mbedtls_internal_ecp_free() functions serve
+ * this purpose.
+ *
+ * To preserve the correct functionality the following conditions must hold:
+ *
+ * - The alternative implementation must be activated by
+ * mbedtls_internal_ecp_init() before any of the replaceable functions is
+ * called.
+ * - mbedtls_internal_ecp_free() must \b only be called when the alternative
+ * implementation is activated.
+ * - mbedtls_internal_ecp_init() must \b not be called when the alternative
+ * implementation is activated.
+ * - Public functions must not return while the alternative implementation is
+ * activated.
+ * - Replaceable functions are guarded by \c MBEDTLS_ECP_XXX_ALT macros and
+ * before calling them an \code if( mbedtls_internal_ecp_grp_capable( grp ) )
+ * \endcode ensures that the alternative implementation supports the current
+ * group.
+ */
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+#endif
+
#if defined(MBEDTLS_ECP_C)
#include "mbedtls/ecp.h"
+#include "mbedtls/threading.h"
+#include "mbedtls/platform_util.h"
#include <string.h>
+#if !defined(MBEDTLS_ECP_ALT)
+
+/* Parameter validation macros based on platform_util.h */
+#define ECP_VALIDATE_RET( cond ) \
+ MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_ECP_BAD_INPUT_DATA )
+#define ECP_VALIDATE( cond ) \
+ MBEDTLS_INTERNAL_VALIDATE( cond )
+
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#define mbedtls_free free
#endif
+#include "mbedtls/ecp_internal.h"
+
#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
!defined(inline) && !defined(__cplusplus)
#define inline __inline
#endif
-/* Implementation that should never be optimized out by the compiler */
-static void mbedtls_zeroize( void *v, size_t n ) {
- volatile unsigned char *p = v; while( n-- ) *p++ = 0;
-}
-
#if defined(MBEDTLS_SELF_TEST)
/*
* Counts of point addition and doubling, and field multiplications.
static unsigned long add_count, dbl_count, mul_count;
#endif
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+/*
+ * Maximum number of "basic operations" to be done in a row.
+ *
+ * Default value 0 means that ECC operations will not yield.
+ * Note that regardless of the value of ecp_max_ops, always at
+ * least one step is performed before yielding.
+ *
+ * Setting ecp_max_ops=1 can be suitable for testing purposes
+ * as it will interrupt computation at all possible points.
+ */
+static unsigned ecp_max_ops = 0;
+
+/*
+ * Set ecp_max_ops
+ */
+void mbedtls_ecp_set_max_ops( unsigned max_ops )
+{
+ ecp_max_ops = max_ops;
+}
+
+/*
+ * Check if restart is enabled
+ */
+int mbedtls_ecp_restart_is_enabled( void )
+{
+ return( ecp_max_ops != 0 );
+}
+
+/*
+ * Restart sub-context for ecp_mul_comb()
+ */
+struct mbedtls_ecp_restart_mul
+{
+ mbedtls_ecp_point R; /* current intermediate result */
+ size_t i; /* current index in various loops, 0 outside */
+ mbedtls_ecp_point *T; /* table for precomputed points */
+ unsigned char T_size; /* number of points in table T */
+ enum { /* what were we doing last time we returned? */
+ ecp_rsm_init = 0, /* nothing so far, dummy initial state */
+ ecp_rsm_pre_dbl, /* precompute 2^n multiples */
+ ecp_rsm_pre_norm_dbl, /* normalize precomputed 2^n multiples */
+ ecp_rsm_pre_add, /* precompute remaining points by adding */
+ ecp_rsm_pre_norm_add, /* normalize all precomputed points */
+ ecp_rsm_comb_core, /* ecp_mul_comb_core() */
+ ecp_rsm_final_norm, /* do the final normalization */
+ } state;
+};
+
+/*
+ * Init restart_mul sub-context
+ */
+static void ecp_restart_rsm_init( mbedtls_ecp_restart_mul_ctx *ctx )
+{
+ mbedtls_ecp_point_init( &ctx->R );
+ ctx->i = 0;
+ ctx->T = NULL;
+ ctx->T_size = 0;
+ ctx->state = ecp_rsm_init;
+}
+
+/*
+ * Free the components of a restart_mul sub-context
+ */
+static void ecp_restart_rsm_free( mbedtls_ecp_restart_mul_ctx *ctx )
+{
+ unsigned char i;
+
+ if( ctx == NULL )
+ return;
+
+ mbedtls_ecp_point_free( &ctx->R );
+
+ if( ctx->T != NULL )
+ {
+ for( i = 0; i < ctx->T_size; i++ )
+ mbedtls_ecp_point_free( ctx->T + i );
+ mbedtls_free( ctx->T );
+ }
+
+ ecp_restart_rsm_init( ctx );
+}
+
+/*
+ * Restart context for ecp_muladd()
+ */
+struct mbedtls_ecp_restart_muladd
+{
+ mbedtls_ecp_point mP; /* mP value */
+ mbedtls_ecp_point R; /* R intermediate result */
+ enum { /* what should we do next? */
+ ecp_rsma_mul1 = 0, /* first multiplication */
+ ecp_rsma_mul2, /* second multiplication */
+ ecp_rsma_add, /* addition */
+ ecp_rsma_norm, /* normalization */
+ } state;
+};
+
+/*
+ * Init restart_muladd sub-context
+ */
+static void ecp_restart_ma_init( mbedtls_ecp_restart_muladd_ctx *ctx )
+{
+ mbedtls_ecp_point_init( &ctx->mP );
+ mbedtls_ecp_point_init( &ctx->R );
+ ctx->state = ecp_rsma_mul1;
+}
+
+/*
+ * Free the components of a restart_muladd sub-context
+ */
+static void ecp_restart_ma_free( mbedtls_ecp_restart_muladd_ctx *ctx )
+{
+ if( ctx == NULL )
+ return;
+
+ mbedtls_ecp_point_free( &ctx->mP );
+ mbedtls_ecp_point_free( &ctx->R );
+
+ ecp_restart_ma_init( ctx );
+}
+
+/*
+ * Initialize a restart context
+ */
+void mbedtls_ecp_restart_init( mbedtls_ecp_restart_ctx *ctx )
+{
+ ECP_VALIDATE( ctx != NULL );
+ ctx->ops_done = 0;
+ ctx->depth = 0;
+ ctx->rsm = NULL;
+ ctx->ma = NULL;
+}
+
+/*
+ * Free the components of a restart context
+ */
+void mbedtls_ecp_restart_free( mbedtls_ecp_restart_ctx *ctx )
+{
+ if( ctx == NULL )
+ return;
+
+ ecp_restart_rsm_free( ctx->rsm );
+ mbedtls_free( ctx->rsm );
+
+ ecp_restart_ma_free( ctx->ma );
+ mbedtls_free( ctx->ma );
+
+ mbedtls_ecp_restart_init( ctx );
+}
+
+/*
+ * Check if we can do the next step
+ */
+int mbedtls_ecp_check_budget( const mbedtls_ecp_group *grp,
+ mbedtls_ecp_restart_ctx *rs_ctx,
+ unsigned ops )
+{
+ ECP_VALIDATE_RET( grp != NULL );
+
+ if( rs_ctx != NULL && ecp_max_ops != 0 )
+ {
+ /* scale depending on curve size: the chosen reference is 256-bit,
+ * and multiplication is quadratic. Round to the closest integer. */
+ if( grp->pbits >= 512 )
+ ops *= 4;
+ else if( grp->pbits >= 384 )
+ ops *= 2;
+
+ /* Avoid infinite loops: always allow first step.
+ * Because of that, however, it's not generally true
+ * that ops_done <= ecp_max_ops, so the check
+ * ops_done > ecp_max_ops below is mandatory. */
+ if( ( rs_ctx->ops_done != 0 ) &&
+ ( rs_ctx->ops_done > ecp_max_ops ||
+ ops > ecp_max_ops - rs_ctx->ops_done ) )
+ {
+ return( MBEDTLS_ERR_ECP_IN_PROGRESS );
+ }
+
+ /* update running count */
+ rs_ctx->ops_done += ops;
+ }
+
+ return( 0 );
+}
+
+/* Call this when entering a function that needs its own sub-context */
+#define ECP_RS_ENTER( SUB ) do { \
+ /* reset ops count for this call if top-level */ \
+ if( rs_ctx != NULL && rs_ctx->depth++ == 0 ) \
+ rs_ctx->ops_done = 0; \
+ \
+ /* set up our own sub-context if needed */ \
+ if( mbedtls_ecp_restart_is_enabled() && \
+ rs_ctx != NULL && rs_ctx->SUB == NULL ) \
+ { \
+ rs_ctx->SUB = mbedtls_calloc( 1, sizeof( *rs_ctx->SUB ) ); \
+ if( rs_ctx->SUB == NULL ) \
+ return( MBEDTLS_ERR_ECP_ALLOC_FAILED ); \
+ \
+ ecp_restart_## SUB ##_init( rs_ctx->SUB ); \
+ } \
+} while( 0 )
+
+/* Call this when leaving a function that needs its own sub-context */
+#define ECP_RS_LEAVE( SUB ) do { \
+ /* clear our sub-context when not in progress (done or error) */ \
+ if( rs_ctx != NULL && rs_ctx->SUB != NULL && \
+ ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) \
+ { \
+ ecp_restart_## SUB ##_free( rs_ctx->SUB ); \
+ mbedtls_free( rs_ctx->SUB ); \
+ rs_ctx->SUB = NULL; \
+ } \
+ \
+ if( rs_ctx != NULL ) \
+ rs_ctx->depth--; \
+} while( 0 )
+
+#else /* MBEDTLS_ECP_RESTARTABLE */
+
+#define ECP_RS_ENTER( sub ) (void) rs_ctx;
+#define ECP_RS_LEAVE( sub ) (void) rs_ctx;
+
+#endif /* MBEDTLS_ECP_RESTARTABLE */
+
#if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) || \
defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) || \
defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) || \
#define ECP_SHORTWEIERSTRASS
#endif
-#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
+#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \
+ defined(MBEDTLS_ECP_DP_CURVE448_ENABLED)
#define ECP_MONTGOMERY
#endif
{
const mbedtls_ecp_curve_info *curve_info;
+ if( name == NULL )
+ return( NULL );
+
for( curve_info = mbedtls_ecp_curve_list();
curve_info->grp_id != MBEDTLS_ECP_DP_NONE;
curve_info++ )
*/
void mbedtls_ecp_point_init( mbedtls_ecp_point *pt )
{
- if( pt == NULL )
- return;
+ ECP_VALIDATE( pt != NULL );
mbedtls_mpi_init( &pt->X );
mbedtls_mpi_init( &pt->Y );
*/
void mbedtls_ecp_group_init( mbedtls_ecp_group *grp )
{
- if( grp == NULL )
- return;
-
- memset( grp, 0, sizeof( mbedtls_ecp_group ) );
+ ECP_VALIDATE( grp != NULL );
+
+ grp->id = MBEDTLS_ECP_DP_NONE;
+ mbedtls_mpi_init( &grp->P );
+ mbedtls_mpi_init( &grp->A );
+ mbedtls_mpi_init( &grp->B );
+ mbedtls_ecp_point_init( &grp->G );
+ mbedtls_mpi_init( &grp->N );
+ grp->pbits = 0;
+ grp->nbits = 0;
+ grp->h = 0;
+ grp->modp = NULL;
+ grp->t_pre = NULL;
+ grp->t_post = NULL;
+ grp->t_data = NULL;
+ grp->T = NULL;
+ grp->T_size = 0;
}
/*
*/
void mbedtls_ecp_keypair_init( mbedtls_ecp_keypair *key )
{
- if( key == NULL )
- return;
+ ECP_VALIDATE( key != NULL );
mbedtls_ecp_group_init( &key->grp );
mbedtls_mpi_init( &key->d );
mbedtls_free( grp->T );
}
- mbedtls_zeroize( grp, sizeof( mbedtls_ecp_group ) );
+ mbedtls_platform_zeroize( grp, sizeof( mbedtls_ecp_group ) );
}
/*
int mbedtls_ecp_copy( mbedtls_ecp_point *P, const mbedtls_ecp_point *Q )
{
int ret;
+ ECP_VALIDATE_RET( P != NULL );
+ ECP_VALIDATE_RET( Q != NULL );
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &P->X, &Q->X ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &P->Y, &Q->Y ) );
*/
int mbedtls_ecp_group_copy( mbedtls_ecp_group *dst, const mbedtls_ecp_group *src )
{
- return mbedtls_ecp_group_load( dst, src->id );
+ ECP_VALIDATE_RET( dst != NULL );
+ ECP_VALIDATE_RET( src != NULL );
+
+ return( mbedtls_ecp_group_load( dst, src->id ) );
}
/*
int mbedtls_ecp_set_zero( mbedtls_ecp_point *pt )
{
int ret;
+ ECP_VALIDATE_RET( pt != NULL );
MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &pt->X , 1 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &pt->Y , 1 ) );
*/
int mbedtls_ecp_is_zero( mbedtls_ecp_point *pt )
{
+ ECP_VALIDATE_RET( pt != NULL );
+
return( mbedtls_mpi_cmp_int( &pt->Z, 0 ) == 0 );
}
/*
- * Compare two points lazyly
+ * Compare two points lazily
*/
int mbedtls_ecp_point_cmp( const mbedtls_ecp_point *P,
const mbedtls_ecp_point *Q )
{
+ ECP_VALIDATE_RET( P != NULL );
+ ECP_VALIDATE_RET( Q != NULL );
+
if( mbedtls_mpi_cmp_mpi( &P->X, &Q->X ) == 0 &&
mbedtls_mpi_cmp_mpi( &P->Y, &Q->Y ) == 0 &&
mbedtls_mpi_cmp_mpi( &P->Z, &Q->Z ) == 0 )
const char *x, const char *y )
{
int ret;
+ ECP_VALIDATE_RET( P != NULL );
+ ECP_VALIDATE_RET( x != NULL );
+ ECP_VALIDATE_RET( y != NULL );
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &P->X, radix, x ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &P->Y, radix, y ) );
/*
* Export a point into unsigned binary data (SEC1 2.3.3)
*/
-int mbedtls_ecp_point_write_binary( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *P,
- int format, size_t *olen,
- unsigned char *buf, size_t buflen )
+int mbedtls_ecp_point_write_binary( const mbedtls_ecp_group *grp,
+ const mbedtls_ecp_point *P,
+ int format, size_t *olen,
+ unsigned char *buf, size_t buflen )
{
int ret = 0;
size_t plen;
-
- if( format != MBEDTLS_ECP_PF_UNCOMPRESSED &&
- format != MBEDTLS_ECP_PF_COMPRESSED )
- return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( P != NULL );
+ ECP_VALIDATE_RET( olen != NULL );
+ ECP_VALIDATE_RET( buf != NULL );
+ ECP_VALIDATE_RET( format == MBEDTLS_ECP_PF_UNCOMPRESSED ||
+ format == MBEDTLS_ECP_PF_COMPRESSED );
/*
* Common case: P == 0
/*
* Import a point from unsigned binary data (SEC1 2.3.4)
*/
-int mbedtls_ecp_point_read_binary( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt,
- const unsigned char *buf, size_t ilen )
+int mbedtls_ecp_point_read_binary( const mbedtls_ecp_group *grp,
+ mbedtls_ecp_point *pt,
+ const unsigned char *buf, size_t ilen )
{
int ret;
size_t plen;
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( pt != NULL );
+ ECP_VALIDATE_RET( buf != NULL );
if( ilen < 1 )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
* opaque point <1..2^8-1>;
* } ECPoint;
*/
-int mbedtls_ecp_tls_read_point( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt,
- const unsigned char **buf, size_t buf_len )
+int mbedtls_ecp_tls_read_point( const mbedtls_ecp_group *grp,
+ mbedtls_ecp_point *pt,
+ const unsigned char **buf, size_t buf_len )
{
unsigned char data_len;
const unsigned char *buf_start;
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( pt != NULL );
+ ECP_VALIDATE_RET( buf != NULL );
+ ECP_VALIDATE_RET( *buf != NULL );
/*
* We must have at least two bytes (1 for length, at least one for data)
buf_start = *buf;
*buf += data_len;
- return mbedtls_ecp_point_read_binary( grp, pt, buf_start, data_len );
+ return( mbedtls_ecp_point_read_binary( grp, pt, buf_start, data_len ) );
}
/*
unsigned char *buf, size_t blen )
{
int ret;
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( pt != NULL );
+ ECP_VALIDATE_RET( olen != NULL );
+ ECP_VALIDATE_RET( buf != NULL );
+ ECP_VALIDATE_RET( format == MBEDTLS_ECP_PF_UNCOMPRESSED ||
+ format == MBEDTLS_ECP_PF_COMPRESSED );
/*
* buffer length must be at least one, for our length byte
/*
* Set a group from an ECParameters record (RFC 4492)
*/
-int mbedtls_ecp_tls_read_group( mbedtls_ecp_group *grp, const unsigned char **buf, size_t len )
+int mbedtls_ecp_tls_read_group( mbedtls_ecp_group *grp,
+ const unsigned char **buf, size_t len )
+{
+ int ret;
+ mbedtls_ecp_group_id grp_id;
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( buf != NULL );
+ ECP_VALIDATE_RET( *buf != NULL );
+
+ if( ( ret = mbedtls_ecp_tls_read_group_id( &grp_id, buf, len ) ) != 0 )
+ return( ret );
+
+ return( mbedtls_ecp_group_load( grp, grp_id ) );
+}
+
+/*
+ * Read a group id from an ECParameters record (RFC 4492) and convert it to
+ * mbedtls_ecp_group_id.
+ */
+int mbedtls_ecp_tls_read_group_id( mbedtls_ecp_group_id *grp,
+ const unsigned char **buf, size_t len )
{
uint16_t tls_id;
const mbedtls_ecp_curve_info *curve_info;
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( buf != NULL );
+ ECP_VALIDATE_RET( *buf != NULL );
/*
* We expect at least three bytes (see below)
if( ( curve_info = mbedtls_ecp_curve_info_from_tls_id( tls_id ) ) == NULL )
return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE );
- return mbedtls_ecp_group_load( grp, curve_info->grp_id );
+ *grp = curve_info->grp_id;
+
+ return( 0 );
}
/*
unsigned char *buf, size_t blen )
{
const mbedtls_ecp_curve_info *curve_info;
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( buf != NULL );
+ ECP_VALIDATE_RET( olen != NULL );
if( ( curve_info = mbedtls_ecp_curve_info_from_grp_id( grp->id ) ) == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
#define INC_MUL_COUNT
#endif
-#define MOD_MUL( N ) do { MBEDTLS_MPI_CHK( ecp_modp( &N, grp ) ); INC_MUL_COUNT } \
- while( 0 )
+#define MOD_MUL( N ) \
+ do \
+ { \
+ MBEDTLS_MPI_CHK( ecp_modp( &(N), grp ) ); \
+ INC_MUL_COUNT \
+ } while( 0 )
/*
* Reduce a mbedtls_mpi mod p in-place, to use after mbedtls_mpi_sub_mpi
* N->s < 0 is a very fast test, which fails only if N is 0
*/
-#define MOD_SUB( N ) \
- while( N.s < 0 && mbedtls_mpi_cmp_int( &N, 0 ) != 0 ) \
- MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &N, &N, &grp->P ) )
+#define MOD_SUB( N ) \
+ while( (N).s < 0 && mbedtls_mpi_cmp_int( &(N), 0 ) != 0 ) \
+ MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &(N), &(N), &grp->P ) )
/*
* Reduce a mbedtls_mpi mod p in-place, to use after mbedtls_mpi_add_mpi and mbedtls_mpi_mul_int.
* We known P, N and the result are positive, so sub_abs is correct, and
* a bit faster.
*/
-#define MOD_ADD( N ) \
- while( mbedtls_mpi_cmp_mpi( &N, &grp->P ) >= 0 ) \
- MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( &N, &N, &grp->P ) )
+#define MOD_ADD( N ) \
+ while( mbedtls_mpi_cmp_mpi( &(N), &grp->P ) >= 0 ) \
+ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( &(N), &(N), &grp->P ) )
#if defined(ECP_SHORTWEIERSTRASS)
/*
if( mbedtls_mpi_cmp_int( &pt->Z, 0 ) == 0 )
return( 0 );
+#if defined(MBEDTLS_ECP_NORMALIZE_JAC_ALT)
+ if( mbedtls_internal_ecp_grp_capable( grp ) )
+ return( mbedtls_internal_ecp_normalize_jac( grp, pt ) );
+#endif /* MBEDTLS_ECP_NORMALIZE_JAC_ALT */
+
mbedtls_mpi_init( &Zi ); mbedtls_mpi_init( &ZZi );
/*
* Cost: 1N(t) := 1I + (6t - 3)M + 1S
*/
static int ecp_normalize_jac_many( const mbedtls_ecp_group *grp,
- mbedtls_ecp_point *T[], size_t t_len )
+ mbedtls_ecp_point *T[], size_t T_size )
{
int ret;
size_t i;
mbedtls_mpi *c, u, Zi, ZZi;
- if( t_len < 2 )
+ if( T_size < 2 )
return( ecp_normalize_jac( grp, *T ) );
- if( ( c = mbedtls_calloc( t_len, sizeof( mbedtls_mpi ) ) ) == NULL )
+#if defined(MBEDTLS_ECP_NORMALIZE_JAC_MANY_ALT)
+ if( mbedtls_internal_ecp_grp_capable( grp ) )
+ return( mbedtls_internal_ecp_normalize_jac_many( grp, T, T_size ) );
+#endif
+
+ if( ( c = mbedtls_calloc( T_size, sizeof( mbedtls_mpi ) ) ) == NULL )
return( MBEDTLS_ERR_ECP_ALLOC_FAILED );
+ for( i = 0; i < T_size; i++ )
+ mbedtls_mpi_init( &c[i] );
+
mbedtls_mpi_init( &u ); mbedtls_mpi_init( &Zi ); mbedtls_mpi_init( &ZZi );
/*
* c[i] = Z_0 * ... * Z_i
*/
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &c[0], &T[0]->Z ) );
- for( i = 1; i < t_len; i++ )
+ for( i = 1; i < T_size; i++ )
{
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &c[i], &c[i-1], &T[i]->Z ) );
MOD_MUL( c[i] );
/*
* u = 1 / (Z_0 * ... * Z_n) mod P
*/
- MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &u, &c[t_len-1], &grp->P ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &u, &c[T_size-1], &grp->P ) );
- for( i = t_len - 1; ; i-- )
+ for( i = T_size - 1; ; i-- )
{
/*
* Zi = 1 / Z_i mod p
cleanup:
mbedtls_mpi_free( &u ); mbedtls_mpi_free( &Zi ); mbedtls_mpi_free( &ZZi );
- for( i = 0; i < t_len; i++ )
+ for( i = 0; i < T_size; i++ )
mbedtls_mpi_free( &c[i] );
mbedtls_free( c );
dbl_count++;
#endif
+#if defined(MBEDTLS_ECP_DOUBLE_JAC_ALT)
+ if( mbedtls_internal_ecp_grp_capable( grp ) )
+ return( mbedtls_internal_ecp_double_jac( grp, R, P ) );
+#endif /* MBEDTLS_ECP_DOUBLE_JAC_ALT */
+
mbedtls_mpi_init( &M ); mbedtls_mpi_init( &S ); mbedtls_mpi_init( &T ); mbedtls_mpi_init( &U );
/* Special case for A = -3 */
add_count++;
#endif
+#if defined(MBEDTLS_ECP_ADD_MIXED_ALT)
+ if( mbedtls_internal_ecp_grp_capable( grp ) )
+ return( mbedtls_internal_ecp_add_mixed( grp, R, P, Q ) );
+#endif /* MBEDTLS_ECP_ADD_MIXED_ALT */
+
/*
* Trivial cases: P == 0 or Q == 0 (case 1)
*/
{
int ret;
mbedtls_mpi l, ll;
- size_t p_size = ( grp->pbits + 7 ) / 8;
+ size_t p_size;
int count = 0;
+#if defined(MBEDTLS_ECP_RANDOMIZE_JAC_ALT)
+ if( mbedtls_internal_ecp_grp_capable( grp ) )
+ return( mbedtls_internal_ecp_randomize_jac( grp, pt, f_rng, p_rng ) );
+#endif /* MBEDTLS_ECP_RANDOMIZE_JAC_ALT */
+
+ p_size = ( grp->pbits + 7 ) / 8;
mbedtls_mpi_init( &l ); mbedtls_mpi_init( &ll );
/* Generate l such that 1 < l < p */
do
{
- mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng ) );
while( mbedtls_mpi_cmp_mpi( &l, &grp->P ) >= 0 )
MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &l, 1 ) );
* modified version that provides resistance to SPA by avoiding zero
* digits in the representation as in [3]. We modify the method further by
* requiring that all K_i be odd, which has the small cost that our
- * representation uses one more K_i, due to carries.
+ * representation uses one more K_i, due to carries, but saves on the size of
+ * the precomputed table.
+ *
+ * Summary of the comb method and its modifications:
*
- * Also, for the sake of compactness, only the seven low-order bits of x[i]
- * are used to represent K_i, and the msb of x[i] encodes the the sign (s_i in
- * the paper): it is set if and only if if s_i == -1;
+ * - The goal is to compute m*P for some w*d-bit integer m.
+ *
+ * - The basic comb method splits m into the w-bit integers
+ * x[0] .. x[d-1] where x[i] consists of the bits in m whose
+ * index has residue i modulo d, and computes m * P as
+ * S[x[0]] + 2 * S[x[1]] + .. + 2^(d-1) S[x[d-1]], where
+ * S[i_{w-1} .. i_0] := i_{w-1} 2^{(w-1)d} P + ... + i_1 2^d P + i_0 P.
+ *
+ * - If it happens that, say, x[i+1]=0 (=> S[x[i+1]]=0), one can replace the sum by
+ * .. + 2^{i-1} S[x[i-1]] - 2^i S[x[i]] + 2^{i+1} S[x[i]] + 2^{i+2} S[x[i+2]] ..,
+ * thereby successively converting it into a form where all summands
+ * are nonzero, at the cost of negative summands. This is the basic idea of [3].
+ *
+ * - More generally, even if x[i+1] != 0, we can first transform the sum as
+ * .. - 2^i S[x[i]] + 2^{i+1} ( S[x[i]] + S[x[i+1]] ) + 2^{i+2} S[x[i+2]] ..,
+ * and then replace S[x[i]] + S[x[i+1]] = S[x[i] ^ x[i+1]] + 2 S[x[i] & x[i+1]].
+ * Performing and iterating this procedure for those x[i] that are even
+ * (keeping track of carry), we can transform the original sum into one of the form
+ * S[x'[0]] +- 2 S[x'[1]] +- .. +- 2^{d-1} S[x'[d-1]] + 2^d S[x'[d]]
+ * with all x'[i] odd. It is therefore only necessary to know S at odd indices,
+ * which is why we are only computing half of it in the first place in
+ * ecp_precompute_comb and accessing it with index abs(i) / 2 in ecp_select_comb.
+ *
+ * - For the sake of compactness, only the seven low-order bits of x[i]
+ * are used to represent its absolute value (K_i in the paper), and the msb
+ * of x[i] encodes the sign (s_i in the paper): it is set if and only if
+ * if s_i == -1;
*
* Calling conventions:
* - x is an array of size d + 1
* - m is the MPI, expected to be odd and such that bitlength(m) <= w * d
* (the result will be incorrect if these assumptions are not satisfied)
*/
-static void ecp_comb_fixed( unsigned char x[], size_t d,
- unsigned char w, const mbedtls_mpi *m )
+static void ecp_comb_recode_core( unsigned char x[], size_t d,
+ unsigned char w, const mbedtls_mpi *m )
{
size_t i, j;
unsigned char c, cc, adjust;
}
/*
- * Precompute points for the comb method
+ * Precompute points for the adapted comb method
*
- * If i = i_{w-1} ... i_1 is the binary representation of i, then
- * T[i] = i_{w-1} 2^{(w-1)d} P + ... + i_1 2^d P + P
+ * Assumption: T must be able to hold 2^{w - 1} elements.
*
- * T must be able to hold 2^{w - 1} elements
+ * Operation: If i = i_{w-1} ... i_1 is the binary representation of i,
+ * sets T[i] = i_{w-1} 2^{(w-1)d} P + ... + i_1 2^d P + P.
*
* Cost: d(w-1) D + (2^{w-1} - 1) A + 1 N(w-1) + 1 N(2^{w-1} - 1)
+ *
+ * Note: Even comb values (those where P would be omitted from the
+ * sum defining T[i] above) are not needed in our adaption
+ * the comb method. See ecp_comb_recode_core().
+ *
+ * This function currently works in four steps:
+ * (1) [dbl] Computation of intermediate T[i] for 2-power values of i
+ * (2) [norm_dbl] Normalization of coordinates of these T[i]
+ * (3) [add] Computation of all T[i]
+ * (4) [norm_add] Normalization of all T[i]
+ *
+ * Step 1 can be interrupted but not the others; together with the final
+ * coordinate normalization they are the largest steps done at once, depending
+ * on the window size. Here are operation counts for P-256:
+ *
+ * step (2) (3) (4)
+ * w = 5 142 165 208
+ * w = 4 136 77 160
+ * w = 3 130 33 136
+ * w = 2 124 11 124
+ *
+ * So if ECC operations are blocking for too long even with a low max_ops
+ * value, it's useful to set MBEDTLS_ECP_WINDOW_SIZE to a lower value in order
+ * to minimize maximum blocking time.
*/
static int ecp_precompute_comb( const mbedtls_ecp_group *grp,
mbedtls_ecp_point T[], const mbedtls_ecp_point *P,
- unsigned char w, size_t d )
+ unsigned char w, size_t d,
+ mbedtls_ecp_restart_ctx *rs_ctx )
{
int ret;
- unsigned char i, k;
- size_t j;
+ unsigned char i;
+ size_t j = 0;
+ const unsigned char T_size = 1U << ( w - 1 );
mbedtls_ecp_point *cur, *TT[COMB_MAX_PRE - 1];
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+ {
+ if( rs_ctx->rsm->state == ecp_rsm_pre_dbl )
+ goto dbl;
+ if( rs_ctx->rsm->state == ecp_rsm_pre_norm_dbl )
+ goto norm_dbl;
+ if( rs_ctx->rsm->state == ecp_rsm_pre_add )
+ goto add;
+ if( rs_ctx->rsm->state == ecp_rsm_pre_norm_add )
+ goto norm_add;
+ }
+#else
+ (void) rs_ctx;
+#endif
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+ {
+ rs_ctx->rsm->state = ecp_rsm_pre_dbl;
+
+ /* initial state for the loop */
+ rs_ctx->rsm->i = 0;
+ }
+
+dbl:
+#endif
/*
* Set T[0] = P and
* T[2^{l-1}] = 2^{dl} P for l = 1 .. w-1 (this is not the final value)
*/
MBEDTLS_MPI_CHK( mbedtls_ecp_copy( &T[0], P ) );
- k = 0;
- for( i = 1; i < ( 1U << ( w - 1 ) ); i <<= 1 )
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL && rs_ctx->rsm->i != 0 )
+ j = rs_ctx->rsm->i;
+ else
+#endif
+ j = 0;
+
+ for( ; j < d * ( w - 1 ); j++ )
{
+ MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_DBL );
+
+ i = 1U << ( j / d );
cur = T + i;
- MBEDTLS_MPI_CHK( mbedtls_ecp_copy( cur, T + ( i >> 1 ) ) );
- for( j = 0; j < d; j++ )
- MBEDTLS_MPI_CHK( ecp_double_jac( grp, cur, cur ) );
- TT[k++] = cur;
+ if( j % d == 0 )
+ MBEDTLS_MPI_CHK( mbedtls_ecp_copy( cur, T + ( i >> 1 ) ) );
+
+ MBEDTLS_MPI_CHK( ecp_double_jac( grp, cur, cur ) );
}
- MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, k ) );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+ rs_ctx->rsm->state = ecp_rsm_pre_norm_dbl;
+
+norm_dbl:
+#endif
+ /*
+ * Normalize current elements in T. As T has holes,
+ * use an auxiliary array of pointers to elements in T.
+ */
+ j = 0;
+ for( i = 1; i < T_size; i <<= 1 )
+ TT[j++] = T + i;
+
+ MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV + 6 * j - 2 );
+ MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, j ) );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+ rs_ctx->rsm->state = ecp_rsm_pre_add;
+
+add:
+#endif
/*
* Compute the remaining ones using the minimal number of additions
* Be careful to update T[2^l] only after using it!
*/
- k = 0;
- for( i = 1; i < ( 1U << ( w - 1 ) ); i <<= 1 )
+ MBEDTLS_ECP_BUDGET( ( T_size - 1 ) * MBEDTLS_ECP_OPS_ADD );
+
+ for( i = 1; i < T_size; i <<= 1 )
{
j = i;
while( j-- )
- {
MBEDTLS_MPI_CHK( ecp_add_mixed( grp, &T[i + j], &T[j], &T[i] ) );
- TT[k++] = &T[i + j];
- }
}
- MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, k ) );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+ rs_ctx->rsm->state = ecp_rsm_pre_norm_add;
+
+norm_add:
+#endif
+ /*
+ * Normalize final elements in T. Even though there are no holes now, we
+ * still need the auxiliary array for homogeneity with the previous
+ * call. Also, skip T[0] which is already normalised, being a copy of P.
+ */
+ for( j = 0; j + 1 < T_size; j++ )
+ TT[j] = T + j + 1;
+
+ MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV + 6 * j - 2 );
+
+ MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, j ) );
cleanup:
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL &&
+ ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
+ {
+ if( rs_ctx->rsm->state == ecp_rsm_pre_dbl )
+ rs_ctx->rsm->i = j;
+ }
+#endif
+
return( ret );
}
/*
* Select precomputed point: R = sign(i) * T[ abs(i) / 2 ]
+ *
+ * See ecp_comb_recode_core() for background
*/
static int ecp_select_comb( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
- const mbedtls_ecp_point T[], unsigned char t_len,
+ const mbedtls_ecp_point T[], unsigned char T_size,
unsigned char i )
{
int ret;
ii = ( i & 0x7Fu ) >> 1;
/* Read the whole table to thwart cache-based timing attacks */
- for( j = 0; j < t_len; j++ )
+ for( j = 0; j < T_size; j++ )
{
MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &R->X, &T[j].X, j == ii ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &R->Y, &T[j].Y, j == ii ) );
* Cost: d A + d D + 1 R
*/
static int ecp_mul_comb_core( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
- const mbedtls_ecp_point T[], unsigned char t_len,
+ const mbedtls_ecp_point T[], unsigned char T_size,
const unsigned char x[], size_t d,
int (*f_rng)(void *, unsigned char *, size_t),
- void *p_rng )
+ void *p_rng,
+ mbedtls_ecp_restart_ctx *rs_ctx )
{
int ret;
mbedtls_ecp_point Txi;
mbedtls_ecp_point_init( &Txi );
- /* Start with a non-zero point and randomize its coordinates */
- i = d;
- MBEDTLS_MPI_CHK( ecp_select_comb( grp, R, T, t_len, x[i] ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &R->Z, 1 ) );
- if( f_rng != 0 )
- MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, R, f_rng, p_rng ) );
+#if !defined(MBEDTLS_ECP_RESTARTABLE)
+ (void) rs_ctx;
+#endif
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL &&
+ rs_ctx->rsm->state != ecp_rsm_comb_core )
+ {
+ rs_ctx->rsm->i = 0;
+ rs_ctx->rsm->state = ecp_rsm_comb_core;
+ }
+
+ /* new 'if' instead of nested for the sake of the 'else' branch */
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL && rs_ctx->rsm->i != 0 )
+ {
+ /* restore current index (R already pointing to rs_ctx->rsm->R) */
+ i = rs_ctx->rsm->i;
+ }
+ else
+#endif
+ {
+ /* Start with a non-zero point and randomize its coordinates */
+ i = d;
+ MBEDTLS_MPI_CHK( ecp_select_comb( grp, R, T, T_size, x[i] ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &R->Z, 1 ) );
+ if( f_rng != 0 )
+ MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, R, f_rng, p_rng ) );
+ }
- while( i-- != 0 )
+ while( i != 0 )
{
+ MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_DBL + MBEDTLS_ECP_OPS_ADD );
+ --i;
+
MBEDTLS_MPI_CHK( ecp_double_jac( grp, R, R ) );
- MBEDTLS_MPI_CHK( ecp_select_comb( grp, &Txi, T, t_len, x[i] ) );
+ MBEDTLS_MPI_CHK( ecp_select_comb( grp, &Txi, T, T_size, x[i] ) );
MBEDTLS_MPI_CHK( ecp_add_mixed( grp, R, R, &Txi ) );
}
cleanup:
+
mbedtls_ecp_point_free( &Txi );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL &&
+ ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
+ {
+ rs_ctx->rsm->i = i;
+ /* no need to save R, already pointing to rs_ctx->rsm->R */
+ }
+#endif
+
return( ret );
}
/*
- * Multiplication using the comb method,
- * for curves in short Weierstrass form
- */
-static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
- const mbedtls_mpi *m, const mbedtls_ecp_point *P,
- int (*f_rng)(void *, unsigned char *, size_t),
- void *p_rng )
+ * Recode the scalar to get constant-time comb multiplication
+ *
+ * As the actual scalar recoding needs an odd scalar as a starting point,
+ * this wrapper ensures that by replacing m by N - m if necessary, and
+ * informs the caller that the result of multiplication will be negated.
+ *
+ * This works because we only support large prime order for Short Weierstrass
+ * curves, so N is always odd hence either m or N - m is.
+ *
+ * See ecp_comb_recode_core() for background.
+ */
+static int ecp_comb_recode_scalar( const mbedtls_ecp_group *grp,
+ const mbedtls_mpi *m,
+ unsigned char k[COMB_MAX_D + 1],
+ size_t d,
+ unsigned char w,
+ unsigned char *parity_trick )
{
int ret;
- unsigned char w, m_is_odd, p_eq_g, pre_len, i;
- size_t d;
- unsigned char k[COMB_MAX_D + 1];
- mbedtls_ecp_point *T;
mbedtls_mpi M, mm;
mbedtls_mpi_init( &M );
mbedtls_mpi_init( &mm );
- /* we need N to be odd to trnaform m in an odd number, check now */
+ /* N is always odd (see above), just make extra sure */
if( mbedtls_mpi_get_bit( &grp->N, 0 ) != 1 )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+ /* do we need the parity trick? */
+ *parity_trick = ( mbedtls_mpi_get_bit( m, 0 ) == 0 );
+
+ /* execute parity fix in constant time */
+ MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &M, m ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &mm, &grp->N, m ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &M, &mm, *parity_trick ) );
+
+ /* actual scalar recoding */
+ ecp_comb_recode_core( k, d, w, &M );
+
+cleanup:
+ mbedtls_mpi_free( &mm );
+ mbedtls_mpi_free( &M );
+
+ return( ret );
+}
+
+/*
+ * Perform comb multiplication (for short Weierstrass curves)
+ * once the auxiliary table has been pre-computed.
+ *
+ * Scalar recoding may use a parity trick that makes us compute -m * P,
+ * if that is the case we'll need to recover m * P at the end.
+ */
+static int ecp_mul_comb_after_precomp( const mbedtls_ecp_group *grp,
+ mbedtls_ecp_point *R,
+ const mbedtls_mpi *m,
+ const mbedtls_ecp_point *T,
+ unsigned char T_size,
+ unsigned char w,
+ size_t d,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng,
+ mbedtls_ecp_restart_ctx *rs_ctx )
+{
+ int ret;
+ unsigned char parity_trick;
+ unsigned char k[COMB_MAX_D + 1];
+ mbedtls_ecp_point *RR = R;
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+ {
+ RR = &rs_ctx->rsm->R;
+
+ if( rs_ctx->rsm->state == ecp_rsm_final_norm )
+ goto final_norm;
+ }
+#endif
+
+ MBEDTLS_MPI_CHK( ecp_comb_recode_scalar( grp, m, k, d, w,
+ &parity_trick ) );
+ MBEDTLS_MPI_CHK( ecp_mul_comb_core( grp, RR, T, T_size, k, d,
+ f_rng, p_rng, rs_ctx ) );
+ MBEDTLS_MPI_CHK( ecp_safe_invert_jac( grp, RR, parity_trick ) );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+ rs_ctx->rsm->state = ecp_rsm_final_norm;
+
+final_norm:
+#endif
+ MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV );
+ MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, RR ) );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+ MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, RR ) );
+#endif
+
+cleanup:
+ return( ret );
+}
+
+/*
+ * Pick window size based on curve size and whether we optimize for base point
+ */
+static unsigned char ecp_pick_window_size( const mbedtls_ecp_group *grp,
+ unsigned char p_eq_g )
+{
+ unsigned char w;
+
/*
* Minimize the number of multiplications, that is minimize
* 10 * d * w + 18 * 2^(w-1) + 11 * d + 7 * w, with d = ceil( nbits / w )
* Just adding one avoids upping the cost of the first mul too much,
* and the memory cost too.
*/
-#if MBEDTLS_ECP_FIXED_POINT_OPTIM == 1
- p_eq_g = ( mbedtls_mpi_cmp_mpi( &P->Y, &grp->G.Y ) == 0 &&
- mbedtls_mpi_cmp_mpi( &P->X, &grp->G.X ) == 0 );
if( p_eq_g )
w++;
-#else
- p_eq_g = 0;
-#endif
/*
* Make sure w is within bounds.
if( w >= grp->nbits )
w = 2;
- /* Other sizes that depend on w */
- pre_len = 1U << ( w - 1 );
+ return( w );
+}
+
+/*
+ * Multiplication using the comb method - for curves in short Weierstrass form
+ *
+ * This function is mainly responsible for administrative work:
+ * - managing the restart context if enabled
+ * - managing the table of precomputed points (passed between the below two
+ * functions): allocation, computation, ownership tranfer, freeing.
+ *
+ * It delegates the actual arithmetic work to:
+ * ecp_precompute_comb() and ecp_mul_comb_with_precomp()
+ *
+ * See comments on ecp_comb_recode_core() regarding the computation strategy.
+ */
+static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
+ const mbedtls_mpi *m, const mbedtls_ecp_point *P,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng,
+ mbedtls_ecp_restart_ctx *rs_ctx )
+{
+ int ret;
+ unsigned char w, p_eq_g, i;
+ size_t d;
+ unsigned char T_size, T_ok;
+ mbedtls_ecp_point *T;
+
+ ECP_RS_ENTER( rsm );
+
+ /* Is P the base point ? */
+#if MBEDTLS_ECP_FIXED_POINT_OPTIM == 1
+ p_eq_g = ( mbedtls_mpi_cmp_mpi( &P->Y, &grp->G.Y ) == 0 &&
+ mbedtls_mpi_cmp_mpi( &P->X, &grp->G.X ) == 0 );
+#else
+ p_eq_g = 0;
+#endif
+
+ /* Pick window size and deduce related sizes */
+ w = ecp_pick_window_size( grp, p_eq_g );
+ T_size = 1U << ( w - 1 );
d = ( grp->nbits + w - 1 ) / w;
- /*
- * Prepare precomputed points: if P == G we want to
- * use grp->T if already initialized, or initialize it.
- */
- T = p_eq_g ? grp->T : NULL;
+ /* Pre-computed table: do we have it already for the base point? */
+ if( p_eq_g && grp->T != NULL )
+ {
+ /* second pointer to the same table, will be deleted on exit */
+ T = grp->T;
+ T_ok = 1;
+ }
+ else
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ /* Pre-computed table: do we have one in progress? complete? */
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL && rs_ctx->rsm->T != NULL )
+ {
+ /* transfer ownership of T from rsm to local function */
+ T = rs_ctx->rsm->T;
+ rs_ctx->rsm->T = NULL;
+ rs_ctx->rsm->T_size = 0;
- if( T == NULL )
+ /* This effectively jumps to the call to mul_comb_after_precomp() */
+ T_ok = rs_ctx->rsm->state >= ecp_rsm_comb_core;
+ }
+ else
+#endif
+ /* Allocate table if we didn't have any */
{
- T = mbedtls_calloc( pre_len, sizeof( mbedtls_ecp_point ) );
+ T = mbedtls_calloc( T_size, sizeof( mbedtls_ecp_point ) );
if( T == NULL )
{
ret = MBEDTLS_ERR_ECP_ALLOC_FAILED;
goto cleanup;
}
- MBEDTLS_MPI_CHK( ecp_precompute_comb( grp, T, P, w, d ) );
+ for( i = 0; i < T_size; i++ )
+ mbedtls_ecp_point_init( &T[i] );
+
+ T_ok = 0;
+ }
+
+ /* Compute table (or finish computing it) if not done already */
+ if( !T_ok )
+ {
+ MBEDTLS_MPI_CHK( ecp_precompute_comb( grp, T, P, w, d, rs_ctx ) );
if( p_eq_g )
{
+ /* almost transfer ownership of T to the group, but keep a copy of
+ * the pointer to use for calling the next function more easily */
grp->T = T;
- grp->T_size = pre_len;
+ grp->T_size = T_size;
}
}
- /*
- * Make sure M is odd (M = m or M = N - m, since N is odd)
- * using the fact that m * P = - (N - m) * P
- */
- m_is_odd = ( mbedtls_mpi_get_bit( m, 0 ) == 1 );
- MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &M, m ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &mm, &grp->N, m ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &M, &mm, ! m_is_odd ) );
+ /* Actual comb multiplication using precomputed points */
+ MBEDTLS_MPI_CHK( ecp_mul_comb_after_precomp( grp, R, m,
+ T, T_size, w, d,
+ f_rng, p_rng, rs_ctx ) );
- /*
- * Go for comb multiplication, R = M * P
- */
- ecp_comb_fixed( k, d, w, &M );
- MBEDTLS_MPI_CHK( ecp_mul_comb_core( grp, R, T, pre_len, k, d, f_rng, p_rng ) );
+cleanup:
- /*
- * Now get m * P from M * P and normalize it
- */
- MBEDTLS_MPI_CHK( ecp_safe_invert_jac( grp, R, ! m_is_odd ) );
- MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, R ) );
+ /* does T belong to the group? */
+ if( T == grp->T )
+ T = NULL;
-cleanup:
+ /* does T belong to the restart context? */
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->rsm != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS && T != NULL )
+ {
+ /* transfer ownership of T from local function to rsm */
+ rs_ctx->rsm->T_size = T_size;
+ rs_ctx->rsm->T = T;
+ T = NULL;
+ }
+#endif
- if( T != NULL && ! p_eq_g )
+ /* did T belong to us? then let's destroy it! */
+ if( T != NULL )
{
- for( i = 0; i < pre_len; i++ )
+ for( i = 0; i < T_size; i++ )
mbedtls_ecp_point_free( &T[i] );
mbedtls_free( T );
}
- mbedtls_mpi_free( &M );
- mbedtls_mpi_free( &mm );
-
+ /* don't free R while in progress in case R == P */
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
+#endif
+ /* prevent caller from using invalid value */
if( ret != 0 )
mbedtls_ecp_point_free( R );
+ ECP_RS_LEAVE( rsm );
+
return( ret );
}
{
int ret;
+#if defined(MBEDTLS_ECP_NORMALIZE_MXZ_ALT)
+ if( mbedtls_internal_ecp_grp_capable( grp ) )
+ return( mbedtls_internal_ecp_normalize_mxz( grp, P ) );
+#endif /* MBEDTLS_ECP_NORMALIZE_MXZ_ALT */
+
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &P->Z, &P->Z, &grp->P ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &P->X, &P->X, &P->Z ) ); MOD_MUL( P->X );
MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &P->Z, 1 ) );
{
int ret;
mbedtls_mpi l;
- size_t p_size = ( grp->pbits + 7 ) / 8;
+ size_t p_size;
int count = 0;
+#if defined(MBEDTLS_ECP_RANDOMIZE_MXZ_ALT)
+ if( mbedtls_internal_ecp_grp_capable( grp ) )
+ return( mbedtls_internal_ecp_randomize_mxz( grp, P, f_rng, p_rng );
+#endif /* MBEDTLS_ECP_RANDOMIZE_MXZ_ALT */
+
+ p_size = ( grp->pbits + 7 ) / 8;
mbedtls_mpi_init( &l );
/* Generate l such that 1 < l < p */
do
{
- mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng ) );
while( mbedtls_mpi_cmp_mpi( &l, &grp->P ) >= 0 )
MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &l, 1 ) );
int ret;
mbedtls_mpi A, AA, B, BB, E, C, D, DA, CB;
+#if defined(MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT)
+ if( mbedtls_internal_ecp_grp_capable( grp ) )
+ return( mbedtls_internal_ecp_double_add_mxz( grp, R, S, P, Q, d ) );
+#endif /* MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT */
+
mbedtls_mpi_init( &A ); mbedtls_mpi_init( &AA ); mbedtls_mpi_init( &B );
mbedtls_mpi_init( &BB ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &C );
mbedtls_mpi_init( &D ); mbedtls_mpi_init( &DA ); mbedtls_mpi_init( &CB );
#endif /* ECP_MONTGOMERY */
/*
- * Multiplication R = m * P
+ * Restartable multiplication R = m * P
*/
-int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
+int mbedtls_ecp_mul_restartable( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
- int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
+ mbedtls_ecp_restart_ctx *rs_ctx )
{
- int ret;
+ int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+ char is_grp_capable = 0;
+#endif
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( R != NULL );
+ ECP_VALIDATE_RET( m != NULL );
+ ECP_VALIDATE_RET( P != NULL );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ /* reset ops count for this call if top-level */
+ if( rs_ctx != NULL && rs_ctx->depth++ == 0 )
+ rs_ctx->ops_done = 0;
+#endif
- /* Common sanity checks */
- if( mbedtls_mpi_cmp_int( &P->Z, 1 ) != 0 )
- return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+ if( ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) ) )
+ MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) );
+#endif /* MBEDTLS_ECP_INTERNAL_ALT */
- if( ( ret = mbedtls_ecp_check_privkey( grp, m ) ) != 0 ||
- ( ret = mbedtls_ecp_check_pubkey( grp, P ) ) != 0 )
- return( ret );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ /* skip argument check when restarting */
+ if( rs_ctx == NULL || rs_ctx->rsm == NULL )
+#endif
+ {
+ /* check_privkey is free */
+ MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_CHK );
+
+ /* Common sanity checks */
+ MBEDTLS_MPI_CHK( mbedtls_ecp_check_privkey( grp, m ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_check_pubkey( grp, P ) );
+ }
+ ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
#if defined(ECP_MONTGOMERY)
if( ecp_get_type( grp ) == ECP_TYPE_MONTGOMERY )
- return( ecp_mul_mxz( grp, R, m, P, f_rng, p_rng ) );
+ MBEDTLS_MPI_CHK( ecp_mul_mxz( grp, R, m, P, f_rng, p_rng ) );
#endif
#if defined(ECP_SHORTWEIERSTRASS)
if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS )
- return( ecp_mul_comb( grp, R, m, P, f_rng, p_rng ) );
+ MBEDTLS_MPI_CHK( ecp_mul_comb( grp, R, m, P, f_rng, p_rng, rs_ctx ) );
#endif
- return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
+
+cleanup:
+
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+ if( is_grp_capable )
+ mbedtls_internal_ecp_free( grp );
+#endif /* MBEDTLS_ECP_INTERNAL_ALT */
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL )
+ rs_ctx->depth--;
+#endif
+
+ return( ret );
+}
+
+/*
+ * Multiplication R = m * P
+ */
+int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
+ const mbedtls_mpi *m, const mbedtls_ecp_point *P,
+ int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
+{
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( R != NULL );
+ ECP_VALIDATE_RET( m != NULL );
+ ECP_VALIDATE_RET( P != NULL );
+ return( mbedtls_ecp_mul_restartable( grp, R, m, P, f_rng, p_rng, NULL ) );
}
#if defined(ECP_SHORTWEIERSTRASS)
static int mbedtls_ecp_mul_shortcuts( mbedtls_ecp_group *grp,
mbedtls_ecp_point *R,
const mbedtls_mpi *m,
- const mbedtls_ecp_point *P )
+ const mbedtls_ecp_point *P,
+ mbedtls_ecp_restart_ctx *rs_ctx )
{
int ret;
}
else
{
- MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, NULL, NULL ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, R, m, P,
+ NULL, NULL, rs_ctx ) );
}
cleanup:
}
/*
- * Linear combination
+ * Restartable linear combination
* NOT constant-time
*/
-int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
+int mbedtls_ecp_muladd_restartable(
+ mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
- const mbedtls_mpi *n, const mbedtls_ecp_point *Q )
+ const mbedtls_mpi *n, const mbedtls_ecp_point *Q,
+ mbedtls_ecp_restart_ctx *rs_ctx )
{
int ret;
mbedtls_ecp_point mP;
+ mbedtls_ecp_point *pmP = &mP;
+ mbedtls_ecp_point *pR = R;
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+ char is_grp_capable = 0;
+#endif
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( R != NULL );
+ ECP_VALIDATE_RET( m != NULL );
+ ECP_VALIDATE_RET( P != NULL );
+ ECP_VALIDATE_RET( n != NULL );
+ ECP_VALIDATE_RET( Q != NULL );
if( ecp_get_type( grp ) != ECP_TYPE_SHORT_WEIERSTRASS )
return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE );
mbedtls_ecp_point_init( &mP );
- MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, &mP, m, P ) );
- MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, R, n, Q ) );
+ ECP_RS_ENTER( ma );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->ma != NULL )
+ {
+ /* redirect intermediate results to restart context */
+ pmP = &rs_ctx->ma->mP;
+ pR = &rs_ctx->ma->R;
+
+ /* jump to next operation */
+ if( rs_ctx->ma->state == ecp_rsma_mul2 )
+ goto mul2;
+ if( rs_ctx->ma->state == ecp_rsma_add )
+ goto add;
+ if( rs_ctx->ma->state == ecp_rsma_norm )
+ goto norm;
+ }
+#endif /* MBEDTLS_ECP_RESTARTABLE */
+
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, pmP, m, P, rs_ctx ) );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->ma != NULL )
+ rs_ctx->ma->state = ecp_rsma_mul2;
+
+mul2:
+#endif
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, pR, n, Q, rs_ctx ) );
+
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+ if( ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) ) )
+ MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) );
+#endif /* MBEDTLS_ECP_INTERNAL_ALT */
- MBEDTLS_MPI_CHK( ecp_add_mixed( grp, R, &mP, R ) );
- MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, R ) );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->ma != NULL )
+ rs_ctx->ma->state = ecp_rsma_add;
+
+add:
+#endif
+ MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_ADD );
+ MBEDTLS_MPI_CHK( ecp_add_mixed( grp, pR, pmP, pR ) );
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->ma != NULL )
+ rs_ctx->ma->state = ecp_rsma_norm;
+
+norm:
+#endif
+ MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV );
+ MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, pR ) );
+
+#if defined(MBEDTLS_ECP_RESTARTABLE)
+ if( rs_ctx != NULL && rs_ctx->ma != NULL )
+ MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, pR ) );
+#endif
cleanup:
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+ if( is_grp_capable )
+ mbedtls_internal_ecp_free( grp );
+#endif /* MBEDTLS_ECP_INTERNAL_ALT */
+
mbedtls_ecp_point_free( &mP );
+ ECP_RS_LEAVE( ma );
+
return( ret );
}
+/*
+ * Linear combination
+ * NOT constant-time
+ */
+int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
+ const mbedtls_mpi *m, const mbedtls_ecp_point *P,
+ const mbedtls_mpi *n, const mbedtls_ecp_point *Q )
+{
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( R != NULL );
+ ECP_VALIDATE_RET( m != NULL );
+ ECP_VALIDATE_RET( P != NULL );
+ ECP_VALIDATE_RET( n != NULL );
+ ECP_VALIDATE_RET( Q != NULL );
+ return( mbedtls_ecp_muladd_restartable( grp, R, m, P, n, Q, NULL ) );
+}
#if defined(ECP_MONTGOMERY)
/*
static int ecp_check_pubkey_mx( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt )
{
/* [Curve25519 p. 5] Just check X is the correct number of bytes */
+ /* Allow any public value, if it's too big then we'll just reduce it mod p
+ * (RFC 7748 sec. 5 para. 3). */
if( mbedtls_mpi_size( &pt->X ) > ( grp->nbits + 7 ) / 8 )
return( MBEDTLS_ERR_ECP_INVALID_KEY );
/*
* Check that a point is valid as a public key
*/
-int mbedtls_ecp_check_pubkey( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt )
+int mbedtls_ecp_check_pubkey( const mbedtls_ecp_group *grp,
+ const mbedtls_ecp_point *pt )
{
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( pt != NULL );
+
/* Must use affine coordinates */
if( mbedtls_mpi_cmp_int( &pt->Z, 1 ) != 0 )
return( MBEDTLS_ERR_ECP_INVALID_KEY );
/*
* Check that an mbedtls_mpi is valid as a private key
*/
-int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, const mbedtls_mpi *d )
+int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp,
+ const mbedtls_mpi *d )
{
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( d != NULL );
+
#if defined(ECP_MONTGOMERY)
if( ecp_get_type( grp ) == ECP_TYPE_MONTGOMERY )
{
- /* see [Curve25519] page 5 */
+ /* see RFC 7748 sec. 5 para. 5 */
if( mbedtls_mpi_get_bit( d, 0 ) != 0 ||
mbedtls_mpi_get_bit( d, 1 ) != 0 ||
- mbedtls_mpi_get_bit( d, 2 ) != 0 ||
mbedtls_mpi_bitlen( d ) - 1 != grp->nbits ) /* mbedtls_mpi_bitlen is one-based! */
return( MBEDTLS_ERR_ECP_INVALID_KEY );
- else
- return( 0 );
+
+ /* see [Curve25519] page 5 */
+ if( grp->nbits == 254 && mbedtls_mpi_get_bit( d, 2 ) != 0 )
+ return( MBEDTLS_ERR_ECP_INVALID_KEY );
+
+ return( 0 );
}
#endif /* ECP_MONTGOMERY */
#if defined(ECP_SHORTWEIERSTRASS)
}
/*
- * Generate a keypair with configurable base point
+ * Generate a private key
*/
-int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
- const mbedtls_ecp_point *G,
- mbedtls_mpi *d, mbedtls_ecp_point *Q,
+int mbedtls_ecp_gen_privkey( const mbedtls_ecp_group *grp,
+ mbedtls_mpi *d,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
- int ret;
- size_t n_size = ( grp->nbits + 7 ) / 8;
+ int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
+ size_t n_size;
+
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( d != NULL );
+ ECP_VALIDATE_RET( f_rng != NULL );
+
+ n_size = ( grp->nbits + 7 ) / 8;
#if defined(ECP_MONTGOMERY)
if( ecp_get_type( grp ) == ECP_TYPE_MONTGOMERY )
else
MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, grp->nbits, 1 ) );
- /* Make sure the last three bits are unset */
+ /* Make sure the last two bits are unset for Curve448, three bits for
+ Curve25519 */
MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 0, 0 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 1, 0 ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 2, 0 ) );
+ if( grp->nbits == 254 )
+ {
+ MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 2, 0 ) );
+ }
}
- else
#endif /* ECP_MONTGOMERY */
+
#if defined(ECP_SHORTWEIERSTRASS)
if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS )
{
/* SEC1 3.2.1: Generate d such that 1 <= n < N */
int count = 0;
- unsigned char rnd[MBEDTLS_ECP_MAX_BYTES];
/*
* Match the procedure given in RFC 6979 (deterministic ECDSA):
*/
do
{
- MBEDTLS_MPI_CHK( f_rng( p_rng, rnd, n_size ) );
- MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( d, rnd, n_size ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( d, n_size, f_rng, p_rng ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( d, 8 * n_size - grp->nbits ) );
/*
while( mbedtls_mpi_cmp_int( d, 1 ) < 0 ||
mbedtls_mpi_cmp_mpi( d, &grp->N ) >= 0 );
}
- else
#endif /* ECP_SHORTWEIERSTRASS */
- return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
cleanup:
- if( ret != 0 )
- return( ret );
+ return( ret );
+}
- return( mbedtls_ecp_mul( grp, Q, d, G, f_rng, p_rng ) );
+/*
+ * Generate a keypair with configurable base point
+ */
+int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
+ const mbedtls_ecp_point *G,
+ mbedtls_mpi *d, mbedtls_ecp_point *Q,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng )
+{
+ int ret;
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( d != NULL );
+ ECP_VALIDATE_RET( G != NULL );
+ ECP_VALIDATE_RET( Q != NULL );
+ ECP_VALIDATE_RET( f_rng != NULL );
+
+ MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, d, f_rng, p_rng ) );
+ MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, Q, d, G, f_rng, p_rng ) );
+
+cleanup:
+ return( ret );
}
/*
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
+ ECP_VALIDATE_RET( grp != NULL );
+ ECP_VALIDATE_RET( d != NULL );
+ ECP_VALIDATE_RET( Q != NULL );
+ ECP_VALIDATE_RET( f_rng != NULL );
+
return( mbedtls_ecp_gen_keypair_base( grp, &grp->G, d, Q, f_rng, p_rng ) );
}
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
{
int ret;
+ ECP_VALIDATE_RET( key != NULL );
+ ECP_VALIDATE_RET( f_rng != NULL );
if( ( ret = mbedtls_ecp_group_load( &key->grp, grp_id ) ) != 0 )
return( ret );
int ret;
mbedtls_ecp_point Q;
mbedtls_ecp_group grp;
+ ECP_VALIDATE_RET( pub != NULL );
+ ECP_VALIDATE_RET( prv != NULL );
if( pub->grp.id == MBEDTLS_ECP_DP_NONE ||
pub->grp.id != prv->grp.id ||
#endif /* MBEDTLS_SELF_TEST */
+#endif /* !MBEDTLS_ECP_ALT */
+
#endif /* MBEDTLS_ECP_C */
projects / platform / upstream / iotivity.git / blobdiff