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Introduce wrapper for modular multiplication with single-width const

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Signed-off-by: Hanno Becker <hanno.becker@arm.com>
This commit is contained in:
Hanno Becker
2022-01-01 06:54:25 +00:00
parent 5c8ea307b8
commit 02b35bd00a
1 changed files with 20 additions and 7 deletions
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27
library/ecp.c
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@ -1138,6 +1138,19 @@ cleanup:
return( ret ); return( ret );
} }
static inline int mbedtls_mpi_mul_int_mod( const mbedtls_ecp_group *grp,
mbedtls_mpi *X,
const mbedtls_mpi *A,
mbedtls_mpi_uint c )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( X, A, c ) );
MOD_ADD( *X );
cleanup:
return( ret );
}
#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) && \ #if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) && \
!( defined(MBEDTLS_ECP_NO_FALLBACK) && \ !( defined(MBEDTLS_ECP_NO_FALLBACK) && \
defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) && \ defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) && \
@ -1372,17 +1385,17 @@ static int ecp_double_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
if( grp->A.p == NULL ) if( grp->A.p == NULL )
{ {
/* M = 3(X + Z^2)(X - Z^2) */ /* M = 3(X + Z^2)(X - Z^2) */
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mod( grp, &S, &P->Z, &P->Z ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mod( grp, &S, &P->Z, &P->Z ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_add_mod( grp, &T, &P->X, &S ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_add_mod( grp, &T, &P->X, &S ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mod( grp, &U, &P->X, &S ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mod( grp, &U, &P->X, &S ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mod( grp, &S, &T, &U ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mod( grp, &S, &T, &U ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( &M, &S, 3 ) ); MOD_ADD( M ); MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int_mod( grp, &M, &S, 3 ) );
} }
else else
{ {
/* M = 3.X^2 */ /* M = 3.X^2 */
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mod( grp, &S, &P->X, &P->X ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mod ( grp, &S, &P->X, &P->X ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( &M, &S, 3 ) ); MOD_ADD( M ); MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int_mod( grp, &M, &S, 3 ) );
/* Optimize away for "koblitz" curves with A = 0 */ /* Optimize away for "koblitz" curves with A = 0 */
if( mbedtls_mpi_cmp_int( &grp->A, 0 ) != 0 ) if( mbedtls_mpi_cmp_int( &grp->A, 0 ) != 0 )