diff options
Diffstat (limited to 'crypto/bn/bn_exp.c')
| -rw-r--r-- | crypto/bn/bn_exp.c | 67 |
1 files changed, 55 insertions, 12 deletions
diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index 0a0db370c3..c056a5083f 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -1,5 +1,5 @@ /* crypto/bn/bn_exp.c */ -/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com) +/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written @@ -120,6 +120,38 @@ err: #endif +/* this one works - simple but works */ +int BN_exp(r,a,p,ctx) +BIGNUM *r,*a,*p; +BN_CTX *ctx; + { + int i,bits,ret=0; + BIGNUM *v,*tmp; + + v=ctx->bn[ctx->tos++]; + tmp=ctx->bn[ctx->tos++]; + + if (BN_copy(v,a) == NULL) goto err; + bits=BN_num_bits(p); + + if (BN_is_odd(p)) + { if (BN_copy(r,a) == NULL) goto err; } + else { if (BN_one(r)) goto err; } + + for (i=1; i<bits; i++) + { + if (!BN_sqr(tmp,v,ctx)) goto err; + if (BN_is_bit_set(p,i)) + { + if (!BN_mul(tmp,r,v)) goto err; + } + } + ret=1; +err: + ctx->tos-=2; + return(ret); + } + int BN_mod_exp(r,a,p,m,ctx) BIGNUM *r; BIGNUM *a; @@ -137,7 +169,7 @@ BN_CTX *ctx; /* if ((m->d[m->top-1]&BN_TBIT) && BN_is_odd(m)) */ if (BN_is_odd(m)) - { ret=BN_mod_exp_mont(r,a,p,m,ctx); } + { ret=BN_mod_exp_mont(r,a,p,m,ctx,NULL); } else #endif #ifdef RECP_MUL_MOD @@ -266,17 +298,19 @@ err: /* #endif */ /* #ifdef MONT_MUL_MOD */ -int BN_mod_exp_mont(r,a,p,m,ctx) +int BN_mod_exp_mont(r,a,p,m,ctx,in_mont) BIGNUM *r; BIGNUM *a; BIGNUM *p; BIGNUM *m; BN_CTX *ctx; +BN_MONT_CTX *in_mont; { +#define TABLE_SIZE 16 int i,j,bits,ret=0,wstart,wend,window,wvalue; int start=1; BIGNUM *d,*aa; - BIGNUM *val[16]; + BIGNUM *val[TABLE_SIZE]; BN_MONT_CTX *mont=NULL; if (!(m->d[0] & 1)) @@ -295,8 +329,15 @@ BN_CTX *ctx; /* If this is not done, things will break in the montgomery * part */ - if ((mont=BN_MONT_CTX_new()) == NULL) goto err; - if (!BN_MONT_CTX_set(mont,m,ctx)) goto err; +#if 1 + if (in_mont != NULL) + mont=in_mont; + else +#endif + { + if ((mont=BN_MONT_CTX_new()) == NULL) goto err; + if (!BN_MONT_CTX_set(mont,m,ctx)) goto err; + } val[0]=BN_new(); if (BN_ucmp(a,m) >= 0) @@ -309,11 +350,11 @@ BN_CTX *ctx; if (!BN_to_montgomery(val[0],aa,mont,ctx)) goto err; /* 1 */ if (!BN_mod_mul_montgomery(d,val[0],val[0],mont,ctx)) goto err; /* 2 */ - if (bits <= 17) /* This is probably 3 or 0x10001, so just do singles */ + if (bits <= 20) /* This is probably 3 or 0x10001, so just do singles */ window=1; - else if (bits >= 256) + else if (bits > 250) window=5; /* max size of window */ - else if (bits >= 128) + else if (bits >= 120) window=4; else window=3; @@ -325,7 +366,7 @@ BN_CTX *ctx; if (!BN_mod_mul_montgomery(val[i],val[i-1],d,mont,ctx)) goto err; } - for (; i<16; i++) + for (; i<TABLE_SIZE; i++) val[i]=NULL; start=1; /* This is used to avoid multiplication etc @@ -341,8 +382,10 @@ BN_CTX *ctx; if (BN_is_bit_set(p,wstart) == 0) { if (!start) + { if (!BN_mod_mul_montgomery(r,r,r,mont,ctx)) goto err; + } if (wstart == 0) break; wstart--; continue; @@ -388,9 +431,9 @@ BN_CTX *ctx; BN_from_montgomery(r,r,mont,ctx); ret=1; err: - if (mont != NULL) BN_MONT_CTX_free(mont); + if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); ctx->tos--; - for (i=0; i<16; i++) + for (i=0; i<TABLE_SIZE; i++) if (val[i] != NULL) BN_clear_free(val[i]); return(ret); } |