diff options
Diffstat (limited to 'crypto/openssl/crypto/bn/bn_exp.c')
| -rw-r--r-- | crypto/openssl/crypto/bn/bn_exp.c | 348 |
1 files changed, 250 insertions, 98 deletions
diff --git a/crypto/openssl/crypto/bn/bn_exp.c b/crypto/openssl/crypto/bn/bn_exp.c index 0c11601..8117323 100644 --- a/crypto/openssl/crypto/bn/bn_exp.c +++ b/crypto/openssl/crypto/bn/bn_exp.c @@ -55,6 +55,60 @@ * copied and put under another distribution licence * [including the GNU Public Licence.] */ +/* ==================================================================== + * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. All advertising materials mentioning features or use of this + * software must display the following acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" + * + * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to + * endorse or promote products derived from this software without + * prior written permission. For written permission, please contact + * openssl-core@openssl.org. + * + * 5. Products derived from this software may not be called "OpenSSL" + * nor may "OpenSSL" appear in their names without prior written + * permission of the OpenSSL Project. + * + * 6. Redistributions of any form whatsoever must retain the following + * acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit (http://www.openssl.org/)" + * + * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY + * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR + * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + * ==================================================================== + * + * This product includes cryptographic software written by Eric Young + * (eay@cryptsoft.com). This product includes software written by Tim + * Hudson (tjh@cryptsoft.com). + * + */ + #include <stdio.h> #include "cryptlib.h" @@ -66,7 +120,8 @@ # include <dlfcn.h> #endif -#define TABLE_SIZE 16 + +#define TABLE_SIZE 32 /* slow but works */ int BN_mod_mul(BIGNUM *ret, BIGNUM *a, BIGNUM *b, const BIGNUM *m, BN_CTX *ctx) @@ -91,42 +146,6 @@ err: return(r); } -#if 0 -/* this one works - simple but works */ -int BN_mod_exp(BIGNUM *r, BIGNUM *a, BIGNUM *p, BIGNUM *m, BN_CTX *ctx) - { - int i,bits,ret=0; - BIGNUM *v,*tmp; - - BN_CTX_start(ctx); - v = BN_CTX_get(ctx); - tmp = BN_CTX_get(ctx); - if (v == NULL || tmp == NULL) goto err; - - 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_mod(v,tmp,m,ctx)) goto err; - if (BN_is_bit_set(p,i)) - { - if (!BN_mul(tmp,r,v,ctx)) goto err; - if (!BN_mod(r,tmp,m,ctx)) goto err; - } - } - ret=1; -err: - BN_CTX_end(ctx); - return(ret); - } - -#endif /* this one works - simple but works */ int BN_exp(BIGNUM *r, BIGNUM *a, BIGNUM *p, BN_CTX *ctx) @@ -163,6 +182,7 @@ err: return(ret); } + #ifdef ATALLA /* @@ -330,6 +350,7 @@ int BN_mod_exp_atalla(BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m) } #endif /* def ATALLA */ + int BN_mod_exp(BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx) { @@ -354,7 +375,15 @@ int BN_mod_exp(BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, /* 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,NULL); } + { + if (a->top == 1) + { + BN_ULONG A = a->d[0]; + ret=BN_mod_exp_mont_word(r,A,p,m,ctx,NULL); + } + else + ret=BN_mod_exp_mont(r,a,p,m,ctx,NULL); + } else #endif #ifdef RECP_MUL_MOD @@ -370,7 +399,7 @@ int BN_mod_exp(BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, return(ret); } -/* #ifdef RECP_MUL_MOD */ + int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx) { @@ -398,27 +427,22 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, ts=1; if (!BN_mod(&(val[0]),a,m,ctx)) goto err; /* 1 */ - if (!BN_mod_mul_reciprocal(aa,&(val[0]),&(val[0]),&recp,ctx)) - goto err; /* 2 */ - - if (bits <= 17) /* This is probably 3 or 0x10001, so just do singles */ - window=1; - else if (bits >= 256) - window=5; /* max size of window */ - else if (bits >= 128) - window=4; - else - window=3; - j=1<<(window-1); - for (i=1; i<j; i++) + window = BN_window_bits_for_exponent_size(bits); + if (window > 1) { - BN_init(&val[i]); - if (!BN_mod_mul_reciprocal(&(val[i]),&(val[i-1]),aa,&recp,ctx)) - goto err; + if (!BN_mod_mul_reciprocal(aa,&(val[0]),&(val[0]),&recp,ctx)) + goto err; /* 2 */ + j=1<<(window-1); + for (i=1; i<j; i++) + { + BN_init(&val[i]); + if (!BN_mod_mul_reciprocal(&(val[i]),&(val[i-1]),aa,&recp,ctx)) + goto err; + } + ts=i; } - ts=i; - + start=1; /* This is used to avoid multiplication etc * when there is only the value '1' in the * buffer. */ @@ -485,9 +509,8 @@ err: BN_RECP_CTX_free(&recp); return(ret); } -/* #endif */ -/* #ifdef MONT_MUL_MOD */ + int BN_mod_exp_mont(BIGNUM *rr, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont) { @@ -527,11 +550,9 @@ int BN_mod_exp_mont(BIGNUM *rr, BIGNUM *a, const BIGNUM *p, /* If this is not done, things will break in the montgomery * part */ -#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; @@ -541,31 +562,27 @@ int BN_mod_exp_mont(BIGNUM *rr, BIGNUM *a, const BIGNUM *p, ts=1; if (BN_ucmp(a,m) >= 0) { - BN_mod(&(val[0]),a,m,ctx); + if (!BN_mod(&(val[0]),a,m,ctx)) + goto err; aa= &(val[0]); } else aa=a; 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 <= 20) /* This is probably 3 or 0x10001, so just do singles */ - window=1; - else if (bits >= 256) - window=5; /* max size of window */ - else if (bits >= 128) - window=4; - else - window=3; - j=1<<(window-1); - for (i=1; i<j; i++) + window = BN_window_bits_for_exponent_size(bits); + if (window > 1) { - BN_init(&(val[i])); - if (!BN_mod_mul_montgomery(&(val[i]),&(val[i-1]),d,mont,ctx)) - goto err; + if (!BN_mod_mul_montgomery(d,&(val[0]),&(val[0]),mont,ctx)) goto err; /* 2 */ + j=1<<(window-1); + for (i=1; i<j; i++) + { + BN_init(&(val[i])); + if (!BN_mod_mul_montgomery(&(val[i]),&(val[i-1]),d,mont,ctx)) + goto err; + } + ts=i; } - ts=i; start=1; /* This is used to avoid multiplication etc * when there is only the value '1' in the @@ -574,7 +591,7 @@ int BN_mod_exp_mont(BIGNUM *rr, BIGNUM *a, const BIGNUM *p, wstart=bits-1; /* The top bit of the window */ wend=0; /* The bottom bit of the window */ - if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err; + if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err; for (;;) { if (BN_is_bit_set(p,wstart) == 0) @@ -626,7 +643,7 @@ int BN_mod_exp_mont(BIGNUM *rr, BIGNUM *a, const BIGNUM *p, start=0; if (wstart < 0) break; } - BN_from_montgomery(rr,r,mont,ctx); + if (!BN_from_montgomery(rr,r,mont,ctx)) goto err; ret=1; err: if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); @@ -635,7 +652,147 @@ err: BN_clear_free(&(val[i])); return(ret); } -/* #endif */ + +int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, + const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont) + { + BN_MONT_CTX *mont = NULL; + int b, bits, ret=0; + int r_is_one; + BN_ULONG w, next_w; + BIGNUM *d, *r, *t; + BIGNUM *swap_tmp; +#define BN_MOD_MUL_WORD(r, w, m) \ + (BN_mul_word(r, (w)) && \ + (/* BN_ucmp(r, (m)) < 0 ? 1 :*/ \ + (BN_mod(t, r, m, ctx) && (swap_tmp = r, r = t, t = swap_tmp, 1)))) + /* BN_MOD_MUL_WORD is only used with 'w' large, + * so the BN_ucmp test is probably more overhead + * than always using BN_mod (which uses BN_copy if + * a similar test returns true). */ +#define BN_TO_MONTGOMERY_WORD(r, w, mont) \ + (BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont), ctx)) + + bn_check_top(p); + bn_check_top(m); + + if (!(m->d[0] & 1)) + { + BNerr(BN_F_BN_MOD_EXP_MONT_WORD,BN_R_CALLED_WITH_EVEN_MODULUS); + return(0); + } + bits = BN_num_bits(p); + if (bits == 0) + { + BN_one(rr); + return(1); + } + BN_CTX_start(ctx); + d = BN_CTX_get(ctx); + r = BN_CTX_get(ctx); + t = BN_CTX_get(ctx); + if (d == NULL || r == NULL || t == NULL) goto err; + +#ifdef ATALLA + if (!tried_atalla) + { + BN_set_word(t, a); + if (BN_mod_exp_atalla(rr, t, p, m)) + { + BN_CTX_end(ctx); + return 1; + } + } +/* If it fails, try the other methods */ +#endif + + if (in_mont != NULL) + mont=in_mont; + else + { + if ((mont = BN_MONT_CTX_new()) == NULL) goto err; + if (!BN_MONT_CTX_set(mont, m, ctx)) goto err; + } + + r_is_one = 1; /* except for Montgomery factor */ + + /* bits-1 >= 0 */ + + /* The result is accumulated in the product r*w. */ + w = a; /* bit 'bits-1' of 'p' is always set */ + for (b = bits-2; b >= 0; b--) + { + /* First, square r*w. */ + next_w = w*w; + if ((next_w/w) != w) /* overflow */ + { + if (r_is_one) + { + if (!BN_TO_MONTGOMERY_WORD(r, w, mont)) goto err; + r_is_one = 0; + } + else + { + if (!BN_MOD_MUL_WORD(r, w, m)) goto err; + } + next_w = 1; + } + w = next_w; + if (!r_is_one) + { + if (!BN_mod_mul_montgomery(r, r, r, mont, ctx)) goto err; + } + + /* Second, multiply r*w by 'a' if exponent bit is set. */ + if (BN_is_bit_set(p, b)) + { + next_w = w*a; + if ((next_w/a) != w) /* overflow */ + { + if (r_is_one) + { + if (!BN_TO_MONTGOMERY_WORD(r, w, mont)) goto err; + r_is_one = 0; + } + else + { + if (!BN_MOD_MUL_WORD(r, w, m)) goto err; + } + next_w = a; + } + w = next_w; + } + } + + /* Finally, set r:=r*w. */ + if (w != 1) + { + if (r_is_one) + { + if (!BN_TO_MONTGOMERY_WORD(r, w, mont)) goto err; + r_is_one = 0; + } + else + { + if (!BN_MOD_MUL_WORD(r, w, m)) goto err; + } + } + + if (r_is_one) /* can happen only if a == 1*/ + { + if (!BN_one(rr)) goto err; + } + else + { + if (!BN_from_montgomery(rr, r, mont, ctx)) goto err; + } + ret = 1; +err: + if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); + BN_CTX_end(ctx); + return(ret); + } + /* The old fallback, simple version :-) */ int BN_mod_exp_simple(BIGNUM *r, BIGNUM *a, BIGNUM *p, BIGNUM *m, @@ -660,26 +817,21 @@ int BN_mod_exp_simple(BIGNUM *r, BIGNUM *a, BIGNUM *p, BIGNUM *m, BN_init(&(val[0])); ts=1; if (!BN_mod(&(val[0]),a,m,ctx)) goto err; /* 1 */ - if (!BN_mod_mul(d,&(val[0]),&(val[0]),m,ctx)) - goto err; /* 2 */ - - if (bits <= 17) /* This is probably 3 or 0x10001, so just do singles */ - window=1; - else if (bits >= 256) - window=5; /* max size of window */ - else if (bits >= 128) - window=4; - else - window=3; - j=1<<(window-1); - for (i=1; i<j; i++) + window = BN_window_bits_for_exponent_size(bits); + if (window > 1) { - BN_init(&(val[i])); - if (!BN_mod_mul(&(val[i]),&(val[i-1]),d,m,ctx)) - goto err; + if (!BN_mod_mul(d,&(val[0]),&(val[0]),m,ctx)) + goto err; /* 2 */ + j=1<<(window-1); + for (i=1; i<j; i++) + { + BN_init(&(val[i])); + if (!BN_mod_mul(&(val[i]),&(val[i-1]),d,m,ctx)) + goto err; + } + ts=i; } - ts=i; start=1; /* This is used to avoid multiplication etc * when there is only the value '1' in the |
