deon/gnuk
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

polarssl: use a bigger sliding window when possible

Browse Source
This commit is contained in:
Aurelien Jarno
2017-10-12 22:02:25 +02:00
committed by NIIBE Yutaka
parent 56fb5002bf
commit 43009f39e8
3 changed files with 18 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
polarssl/library/bignum.c
View File

@@ -1666,11 +1666,18 @@ static void mpi_montsqr( size_t n, const t_uint *np, t_uint mm, t_uint *d )
/*
* Sliding-window exponentiation: X = A^E mod N (HAC 14.85)
*/
#if MEMORY_SIZE >= 32
#define MAX_WSIZE 6
#elif MEMORY_SIZE >= 24
#define MAX_WSIZE 5
#else
#define MAX_WSIZE 4
#endif
int mpi_exp_mod( mpi *X, const mpi *A, const mpi *E, const mpi *N, mpi *_RR )
{
int ret;
size_t i = mpi_msb( E );
size_t wsize = ( i > 1024 ) ? 4 : /* Because of not enough memory. */
size_t wsize = ( i > 1024 ) ? MAX_WSIZE :
( i > 671 ) ? 6 : ( i > 239 ) ? 5 :
( i > 79 ) ? 4 : ( i > 23 ) ? 3 : 1;
size_t wbits, one = 1;