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Use much less variables in ecp_double_jac_gen()

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Manuel Pégourié-Gonnard 2013-10-10 12:44:27 +02:00
parent 1c4aa24df1
commit 0ace4b3154
1 changed files with 33 additions and 41 deletions
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74
library/ecp.c
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@ -1109,61 +1109,53 @@ cleanup:
/* /*
* Point doubling R = 2 P, Jacobian coordinates with general A * Point doubling R = 2 P, Jacobian coordinates with general A
*
* http://www.hyperelliptic.org/EFD/g1p/auto-code/shortw/jacobian/doubling/dbl-2007-bl.op3 * http://www.hyperelliptic.org/EFD/g1p/auto-code/shortw/jacobian/doubling/dbl-2007-bl.op3
* with heavy variable renaming, some reordering and one minor modification
* (a = 2 * b, c = d - 2a replaced with c = d, c = c - b, c = c - b)
* in order to use a lot less intermediate variables (6 vs 25).
*/ */
static int ecp_double_jac_gen( const ecp_group *grp, ecp_point *R, static int ecp_double_jac_gen( const ecp_group *grp, ecp_point *R,
const ecp_point *P ) const ecp_point *P )
{ {
int ret; int ret;
mpi XX, YY, YYYY, ZZ, t0, t1, t2, t3, S, t4, t5, t6, M, t7, t8, T, X3, t9, mpi T1, T2, T3, X3, Y3, Z3;
t10, t11, Y3, t12, t13, t14, Z3;
mpi_init( &XX ); mpi_init( &YY ); mpi_init( &YYYY ); mpi_init( &ZZ ); mpi_init( &T1 ); mpi_init( &T2 ); mpi_init( &T3 );
mpi_init( &t0 ); mpi_init( &t1 ); mpi_init( &t2 ); mpi_init( &t3 ); mpi_init( &X3 ); mpi_init( &Y3 ); mpi_init( &Z3 );
mpi_init( &S ); mpi_init( &t4 ); mpi_init( &t5 ); mpi_init( &t6 );
mpi_init( &M ); mpi_init( &t7 ); mpi_init( &t8 ); mpi_init( &T );
mpi_init( &X3 ); mpi_init( &t9 ); mpi_init( &t10 ); mpi_init( &t11 );
mpi_init( &Y3 ); mpi_init( &t12 ); mpi_init( &t13 ); mpi_init( &t14 );
mpi_init( &Z3 );
MPI_CHK( mpi_mul_mpi( &XX, &P->X, &P->X ) ); MOD_MUL( XX ); MPI_CHK( mpi_mul_mpi( &T3, &P->X, &P->X ) ); MOD_MUL( T3 );
MPI_CHK( mpi_mul_mpi( &YY, &P->Y, &P->Y ) ); MOD_MUL( YY ); MPI_CHK( mpi_mul_mpi( &T2, &P->Y, &P->Y ) ); MOD_MUL( T2 );
MPI_CHK( mpi_mul_mpi( &YYYY, &YY, &YY ) ); MOD_MUL( YYYY ); MPI_CHK( mpi_mul_mpi( &Y3, &T2, &T2 ) ); MOD_MUL( Y3 );
MPI_CHK( mpi_mul_mpi( &ZZ, &P->Z, &P->Z ) ); MOD_MUL( ZZ ); MPI_CHK( mpi_add_mpi( &X3, &P->X, &T2 ) ); MOD_ADD( X3 );
MPI_CHK( mpi_add_mpi( &t0, &P->X, &YY ) ); MOD_ADD( t0 ); MPI_CHK( mpi_mul_mpi( &X3, &X3, &X3 ) ); MOD_MUL( X3 );
MPI_CHK( mpi_mul_mpi( &t1, &t0, &t0 ) ); MOD_MUL( t1 ); MPI_CHK( mpi_sub_mpi( &X3, &X3, &Y3 ) ); MOD_SUB( X3 );
MPI_CHK( mpi_sub_mpi( &t2, &t1, &XX ) ); MOD_SUB( t2 ); MPI_CHK( mpi_sub_mpi( &X3, &X3, &T3 ) ); MOD_SUB( X3 );
MPI_CHK( mpi_sub_mpi( &t3, &t2, &YYYY ) ); MOD_SUB( t3 ); MPI_CHK( mpi_mul_int( &T1, &X3, 2 ) ); MOD_ADD( T1 );
MPI_CHK( mpi_mul_int( &S, &t3, 2 ) ); MOD_ADD( S ); MPI_CHK( mpi_mul_mpi( &Z3, &P->Z, &P->Z ) ); MOD_MUL( Z3 );
MPI_CHK( mpi_mul_mpi( &t4, &ZZ, &ZZ ) ); MOD_MUL( t4 ); MPI_CHK( mpi_mul_mpi( &X3, &Z3, &Z3 ) ); MOD_MUL( X3 );
MPI_CHK( mpi_mul_mpi( &t5, &t4, &grp->A ) ); MOD_MUL( t5 ); MPI_CHK( mpi_mul_int( &T3, &T3, 3 ) ); MOD_ADD( T3 );
MPI_CHK( mpi_mul_int( &t6, &XX, 3 ) ); MOD_ADD( t6 ); MPI_CHK( mpi_mul_mpi( &X3, &X3, &grp->A ) ); MOD_MUL( X3 );
MPI_CHK( mpi_add_mpi( &M, &t6, &t5 ) ); MOD_ADD( M ); MPI_CHK( mpi_add_mpi( &T3, &T3, &X3 ) ); MOD_ADD( T3 );
MPI_CHK( mpi_mul_mpi( &t7, &M, &M ) ); MOD_MUL( t7 ); MPI_CHK( mpi_mul_mpi( &X3, &T3, &T3 ) ); MOD_MUL( X3 );
MPI_CHK( mpi_mul_int( &t8, &S, 2 ) ); MOD_ADD( t8 ); MPI_CHK( mpi_sub_mpi( &X3, &X3, &T1 ) ); MOD_SUB( X3 );
MPI_CHK( mpi_sub_mpi( &T, &t7, &t8 ) ); MOD_SUB( T ); MPI_CHK( mpi_sub_mpi( &X3, &X3, &T1 ) ); MOD_SUB( X3 );
MPI_CHK( mpi_copy( &X3, &T ) ); MPI_CHK( mpi_sub_mpi( &T1, &T1, &X3 ) ); MOD_SUB( T1 );
MPI_CHK( mpi_sub_mpi( &t9, &S, &T ) ); MOD_SUB( t9 ); MPI_CHK( mpi_mul_mpi( &T1, &T3, &T1 ) ); MOD_MUL( T1 );
MPI_CHK( mpi_mul_int( &t10, &YYYY, 8 ) ); MOD_ADD( t10 ); MPI_CHK( mpi_mul_int( &T3, &Y3, 8 ) ); MOD_ADD( T3 );
MPI_CHK( mpi_mul_mpi( &t11, &M, &t9 ) ); MOD_MUL( t11 ); MPI_CHK( mpi_sub_mpi( &Y3, &T1, &T3 ) ); MOD_SUB( Y3 );
MPI_CHK( mpi_sub_mpi( &Y3, &t11, &t10 ) ); MOD_SUB( Y3 ); MPI_CHK( mpi_add_mpi( &T1, &P->Y, &P->Z ) ); MOD_ADD( T1 );
MPI_CHK( mpi_add_mpi( &t12, &P->Y, &P->Z ) ); MOD_ADD( t12 ); MPI_CHK( mpi_mul_mpi( &T1, &T1, &T1 ) ); MOD_MUL( T1 );
MPI_CHK( mpi_mul_mpi( &t13, &t12, &t12 ) ); MOD_MUL( t13 ); MPI_CHK( mpi_sub_mpi( &T1, &T1, &T2 ) ); MOD_SUB( T1 );
MPI_CHK( mpi_sub_mpi( &t14, &t13, &YY ) ); MOD_SUB( t14 ); MPI_CHK( mpi_sub_mpi( &Z3, &T1, &Z3 ) ); MOD_SUB( Z3 );
MPI_CHK( mpi_sub_mpi( &Z3, &t14, &ZZ ) ); MOD_SUB( Z3 );
MPI_CHK( mpi_copy( &R->X, &X3 ) ); MPI_CHK( mpi_copy( &R->X, &X3 ) );
MPI_CHK( mpi_copy( &R->Y, &Y3 ) ); MPI_CHK( mpi_copy( &R->Y, &Y3 ) );
MPI_CHK( mpi_copy( &R->Z, &Z3 ) ); MPI_CHK( mpi_copy( &R->Z, &Z3 ) );
cleanup: cleanup:
mpi_free( &XX ); mpi_free( &YY ); mpi_free( &YYYY ); mpi_free( &ZZ ); mpi_free( &T1 ); mpi_free( &T2 ); mpi_free( &T3 );
mpi_free( &t0 ); mpi_free( &t1 ); mpi_free( &t2 ); mpi_free( &t3 ); mpi_free( &X3 ); mpi_free( &Y3 ); mpi_free( &Z3 );
mpi_free( &S ); mpi_free( &t4 ); mpi_free( &t5 ); mpi_free( &t6 );
mpi_free( &M ); mpi_free( &t7 ); mpi_free( &t8 ); mpi_free( &T );
mpi_free( &X3 ); mpi_free( &t9 ); mpi_free( &t10 ); mpi_free( &t11 );
mpi_free( &Y3 ); mpi_free( &t12 ); mpi_free( &t13 ); mpi_free( &t14 );
mpi_free( &Z3 );
return( ret ); return( ret );
} }