diff options
Diffstat (limited to 'crypto/bn/bn_mont.c')
-rw-r--r-- | crypto/bn/bn_mont.c | 45 |
1 files changed, 34 insertions, 11 deletions
diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c index 3c47351962..683e8e946b 100644 --- a/crypto/bn/bn_mont.c +++ b/crypto/bn/bn_mont.c @@ -20,12 +20,23 @@ #define MONT_WORD /* use the faster word-based algorithm */ #ifdef MONT_WORD -static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont); +static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont); #endif int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_MONT_CTX *mont, BN_CTX *ctx) { + int ret = bn_mul_mont_fixed_top(r, a, b, mont, ctx); + + bn_correct_top(r); + bn_check_top(r); + + return ret; +} + +int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, + BN_MONT_CTX *mont, BN_CTX *ctx) +{ BIGNUM *tmp; int ret = 0; int num = mont->N.top; @@ -37,7 +48,7 @@ int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, if (bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) { r->neg = a->neg ^ b->neg; r->top = num; - bn_correct_top(r); + r->flags |= BN_FLG_FIXED_TOP; return 1; } } @@ -61,13 +72,12 @@ int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, } /* reduce from aRR to aR */ #ifdef MONT_WORD - if (!BN_from_montgomery_word(r, tmp, mont)) + if (!bn_from_montgomery_word(r, tmp, mont)) goto err; #else if (!BN_from_montgomery(r, tmp, mont, ctx)) goto err; #endif - bn_check_top(r); ret = 1; err: BN_CTX_end(ctx); @@ -75,7 +85,7 @@ int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, } #ifdef MONT_WORD -static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) +static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) { BIGNUM *n; BN_ULONG *ap, *np, *rp, n0, v, carry; @@ -102,6 +112,7 @@ static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) memset(&rp[r->top], 0, sizeof(*rp) * i); r->top = max; + r->flags |= BN_FLG_FIXED_TOP; n0 = mont->n0[0]; /* @@ -120,6 +131,7 @@ static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) if (bn_wexpand(ret, nl) == NULL) return 0; ret->top = nl; + ret->flags |= BN_FLG_FIXED_TOP; ret->neg = r->neg; rp = ret->d; @@ -140,9 +152,6 @@ static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) rp[i] = (carry & ap[i]) | (~carry & rp[i]); ap[i] = 0; } - bn_correct_top(r); - bn_correct_top(ret); - bn_check_top(ret); return 1; } @@ -156,8 +165,11 @@ int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, BIGNUM *t; BN_CTX_start(ctx); - if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) - retn = BN_from_montgomery_word(ret, t, mont); + if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) { + retn = bn_from_montgomery_word(ret, t, mont); + bn_correct_top(ret); + bn_check_top(ret); + } BN_CTX_end(ctx); #else /* !MONT_WORD */ BIGNUM *t1, *t2; @@ -195,6 +207,12 @@ int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, return retn; } +int bn_to_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont, + BN_CTX *ctx) +{ + return bn_mul_mont_fixed_top(r, a, &(mont->RR), mont, ctx); +} + BN_MONT_CTX *BN_MONT_CTX_new(void) { BN_MONT_CTX *ret; @@ -232,7 +250,7 @@ void BN_MONT_CTX_free(BN_MONT_CTX *mont) int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) { - int ret = 0; + int i, ret = 0; BIGNUM *Ri, *R; if (BN_is_zero(mod)) @@ -367,6 +385,11 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx)) goto err; + for (i = mont->RR.top, ret = mont->N.top; i < ret; i++) + mont->RR.d[i] = 0; + mont->RR.top = ret; + mont->RR.flags |= BN_FLG_FIXED_TOP; + ret = 1; err: BN_CTX_end(ctx); |