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authorKevin B Kenny <kennykb@acm.org>2005-04-10 23:54:55 (GMT)
committerKevin B Kenny <kennykb@acm.org>2005-04-10 23:54:55 (GMT)
commit9c989aeec930a9251ba5eddc6a81898a5c91ee0e (patch)
tree8809a65920a763a8894572aee81a71eeff4b2c82 /libtommath/bn_mp_exptmod.c
parent2168824a1ddf134001dd68311befeb7d58dddd38 (diff)
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Import of tommath 0.35
Diffstat (limited to 'libtommath/bn_mp_exptmod.c')
-rw-r--r--libtommath/bn_mp_exptmod.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/libtommath/bn_mp_exptmod.c b/libtommath/bn_mp_exptmod.c
index 7309170..7c4e2f8 100644
--- a/libtommath/bn_mp_exptmod.c
+++ b/libtommath/bn_mp_exptmod.c
@@ -65,21 +65,29 @@ int mp_exptmod (mp_int * G, mp_int * X, mp_int * P, mp_int * Y)
#endif
}
+/* modified diminished radix reduction */
+#if defined(BN_MP_REDUCE_IS_2K_L_C) && defined(BN_MP_REDUCE_2K_L_C)
+ if (mp_reduce_is_2k_l(P) == MP_YES) {
+ return s_mp_exptmod(G, X, P, Y, 1);
+ }
+#endif
+
#ifdef BN_MP_DR_IS_MODULUS_C
/* is it a DR modulus? */
dr = mp_dr_is_modulus(P);
#else
+ /* default to no */
dr = 0;
#endif
#ifdef BN_MP_REDUCE_IS_2K_C
- /* if not, is it a uDR modulus? */
+ /* if not, is it a unrestricted DR modulus? */
if (dr == 0) {
dr = mp_reduce_is_2k(P) << 1;
}
#endif
- /* if the modulus is odd or dr != 0 use the fast method */
+ /* if the modulus is odd or dr != 0 use the montgomery method */
#ifdef BN_MP_EXPTMOD_FAST_C
if (mp_isodd (P) == 1 || dr != 0) {
return mp_exptmod_fast (G, X, P, Y, dr);
@@ -87,7 +95,7 @@ int mp_exptmod (mp_int * G, mp_int * X, mp_int * P, mp_int * Y)
#endif
#ifdef BN_S_MP_EXPTMOD_C
/* otherwise use the generic Barrett reduction technique */
- return s_mp_exptmod (G, X, P, Y);
+ return s_mp_exptmod (G, X, P, Y, 0);
#else
/* no exptmod for evens */
return MP_VAL;