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Replaced double_generic with double_jac

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Manuel Pégourié-Gonnard 2012-11-08 22:02:42 +01:00 committed by Paul Bakker
parent 27b1ba8be0
commit 989c32bc3e
1 changed files with 83 additions and 68 deletions
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149
library/ecp.c
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@ -216,10 +216,26 @@ typedef struct
}
ecp_ptjac;
/*
* Initialize a point in Jacobian coordinates
*/
static void ecp_ptjac_init( ecp_ptjac *P )
{
mpi_init( &P->X ); mpi_init( &P->Y ); mpi_init( &P->Z );
}
/*
* Free a point in Jacobian cooridnates
*/
static void ecp_ptjac_free( ecp_ptjac *P )
{
mpi_free( &P->X ); mpi_free( &P->Y ); mpi_free( &P->Z );
}
/*
* Convert from affine to Jacobian coordinates
*/
static int ecp_aff_to_jac( ecp_ptjac *jac, ecp_point *aff )
static int ecp_aff_to_jac( ecp_ptjac *jac, const ecp_point *aff )
{
int ret = 0;
@ -244,7 +260,7 @@ cleanup:
* Convert from Jacobian to affine coordinates
*/
static int ecp_jac_to_aff( const ecp_group *grp,
ecp_point *aff, ecp_ptjac *jac )
ecp_point *aff, const ecp_ptjac *jac )
{
int ret = 0;
mpi Zi, ZZi, T;
@ -280,6 +296,58 @@ cleanup:
return( ret );
}
/*
* Point doubling R = 2 P, Jacobian coordinates (GECC 3.21)
*/
static int ecp_double_jac( const ecp_group *grp, ecp_ptjac *R,
const ecp_ptjac *P )
{
int ret = 0;
mpi T1, T2, T3, X, Y, Z;
mpi_init( &T1 ); mpi_init( &T2 ); mpi_init( &T3 );
mpi_init( &X ); mpi_init( &Y ); mpi_init( &Z );
if( mpi_cmp_int( &P->Z, 0 ) == 0 )
{
MPI_CHK( mpi_lset( &R->X, 1 ) );
MPI_CHK( mpi_lset( &R->Y, 1 ) );
MPI_CHK( mpi_lset( &R->Z, 0 ) );
goto cleanup;
}
MPI_CHK( mpi_mul_mpi( &T1, &P->Z, &P->Z ) );
MPI_CHK( mpi_sub_mpi( &T2, &P->X, &T1 ) );
MPI_CHK( mpi_add_mpi( &T1, &P->X, &T1 ) );
MPI_CHK( mpi_mul_mpi( &T2, &T2, &T1 ) );
MPI_CHK( mpi_mul_int( &T2, &T2, 3 ) );
MPI_CHK( mpi_copy ( &Y, &P->Y ) );
MPI_CHK( mpi_shift_l( &Y, 1 ) );
MPI_CHK( mpi_mul_mpi( &Z, &Y, &P->Z ) );
MPI_CHK( mpi_mul_mpi( &Y, &Y, &Y ) );
MPI_CHK( mpi_mul_mpi( &T3, &Y, &P->X ) );
MPI_CHK( mpi_mul_mpi( &Y, &Y, &Y ) );
MPI_CHK( mpi_shift_r( &Y, 1 ) );
MPI_CHK( mpi_mul_mpi( &X, &T2, &T2 ) );
MPI_CHK( mpi_copy ( &T1, &T3 ) );
MPI_CHK( mpi_shift_l( &T1, 1 ) );
MPI_CHK( mpi_sub_mpi( &X, &X, &T1 ) );
MPI_CHK( mpi_sub_mpi( &T1, &T3, &X ) );
MPI_CHK( mpi_mul_mpi( &T1, &T1, &T2 ) );
MPI_CHK( mpi_sub_mpi( &Y, &T1, &Y ) );
MPI_CHK( mpi_mod_mpi( &R->X, &X, &grp->P ) );
MPI_CHK( mpi_mod_mpi( &R->Y, &Y, &grp->P ) );
MPI_CHK( mpi_mod_mpi( &R->Z, &Z, &grp->P ) );
cleanup:
mpi_free( &T1 ); mpi_free( &T2 ); mpi_free( &T3 );
mpi_free( &X ); mpi_free( &Y ); mpi_free( &Z );
return( ret );
}
/*
* Addition: R = P + Q, generic case (P != Q, P != 0, Q != 0, R != 0)
* Cf SEC1 v2 p. 7, item 4
@ -336,66 +404,6 @@ cleanup:
return( ret );
}
/*
* Doubling: R = 2 * P, generic case (P != 0, R != 0)
* Cf SEC1 v2 p. 7, item 5
*/
static int ecp_double_generic( const ecp_group *grp, ecp_point *R,
const ecp_point *P )
{
int ret = 0;
mpi LN, LD, K, L, LL, X, Y;
mpi_init( &LN ); mpi_init( &LD ); mpi_init( &K ); mpi_init( &L );
mpi_init( &LL ); mpi_init( &X ); mpi_init( &Y );
/*
* L = 3 (P.X - 1) (P.X + 1) / (2 P.Y) mod p
*/
MPI_CHK( mpi_copy( &LD, &P->Y ) );
MPI_CHK( mpi_shift_l( &LD, 1 ) );
MPI_CHK( mpi_inv_mod( &K, &LD, &grp->P ) );
MPI_CHK( mpi_mul_int( &K, &K, 3 ) );
MPI_CHK( mpi_sub_int( &LN, &P->X, 1 ) );
MPI_CHK( mpi_mul_mpi( &K, &K, &LN ) );
MPI_CHK( mpi_add_int( &LN, &P->X, 1 ) );
MPI_CHK( mpi_mul_mpi( &K, &K, &LN ) );
MPI_CHK( mpi_mod_mpi( &L, &K, &grp->P ) );
/*
* LL = L^2 mod p
*/
MPI_CHK( mpi_mul_mpi( &LL, &L, &L ) );
MPI_CHK( mpi_mod_mpi( &LL, &LL, &grp->P ) );
/*
* X = L^2 - 2 * P.X
*/
MPI_CHK( mpi_sub_mpi( &X, &LL, &P->X ) );
MPI_CHK( mpi_sub_mpi( &X, &X, &P->X ) );
/*
* Y = L * (P.X - X) - P.Y
*/
MPI_CHK( mpi_sub_mpi( &Y, &P->X, &X) );
MPI_CHK( mpi_mul_mpi( &Y, &Y, &L ) );
MPI_CHK( mpi_sub_mpi( &Y, &Y, &P->Y ) );
/*
* R = (X mod p, Y mod p)
*/
R->is_zero = 0;
MPI_CHK( mpi_mod_mpi( &R->X, &X, &grp->P ) );
MPI_CHK( mpi_mod_mpi( &R->Y, &Y, &grp->P ) );
cleanup:
mpi_free( &LN ); mpi_free( &LD ); mpi_free( &K ); mpi_free( &L );
mpi_free( &LL ); mpi_free( &X ); mpi_free( &Y );
return( ret );
}
/*
* Addition: R = P + Q, cf p. 7 of SEC1 v2
*/
@ -403,6 +411,9 @@ int ecp_add( const ecp_group *grp, ecp_point *R,
const ecp_point *P, const ecp_point *Q )
{
int ret = 0;
ecp_ptjac J;
ecp_ptjac_init( &J );
if( P->is_zero )
{
@ -416,8 +427,7 @@ int ecp_add( const ecp_group *grp, ecp_point *R,
{
ret = ecp_add_generic( grp, R, P, Q );
}
else if( mpi_cmp_int( &P->Y, 0 ) == 0 ||
mpi_cmp_mpi( &P->Y, &Q->Y ) != 0 )
else if( mpi_cmp_mpi( &P->Y, &Q->Y ) != 0 )
{
ecp_set_zero( R );
}
@ -426,15 +436,20 @@ int ecp_add( const ecp_group *grp, ecp_point *R,
/*
* P == Q
*/
ret = ecp_double_generic( grp, R, P );
ecp_aff_to_jac( &J, P );
MPI_CHK( ecp_double_jac( grp, &J, &J ) );
MPI_CHK( ecp_jac_to_aff( grp, R, &J ) );
}
cleanup:
ecp_ptjac_free( &J );
return ret;
}
/*
* Integer multiplication: R = m * P
* GECC 5.7 (SPA-resistant algorithm)
* Integer multiplication: R = m * P (GECC 5.7, SPA-resistant variant)
*/
int ecp_mul( const ecp_group *grp, ecp_point *R,
const mpi *m, const ecp_point *P )