X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_exp.c;h=afdfd580fb43947dc380aa44dccd232d1cc5c5c8;hp=0a0db370c35bcdced30a5d63ecf339ec35e69c71;hb=f13ddd5d0a6dd1dbccdc08ee904c09b3dc890ad1;hpb=b7896b3cb86d80206af14a14d69b0717786f2729 diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index 0a0db370c3..afdfd580fb 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 @@ -55,80 +55,145 @@ * 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 #include "cryptlib.h" #include "bn_lcl.h" -/* slow but works */ -int BN_mod_mul(ret, a, b, m, ctx) -BIGNUM *ret; -BIGNUM *a; -BIGNUM *b; -BIGNUM *m; -BN_CTX *ctx; - { - BIGNUM *t; - int r=0; - - t=ctx->bn[ctx->tos++]; - if (a == b) - { if (!BN_sqr(t,a,ctx)) goto err; } - else - { if (!BN_mul(t,a,b)) goto err; } - if (!BN_mod(ret,t,m,ctx)) goto err; - r=1; -err: - ctx->tos--; - return(r); - } +#define TABLE_SIZE 32 -#if 0 /* this one works - simple but works */ -int BN_mod_exp(r,a,p,m,ctx) -BIGNUM *r,*a,*p,*m; -BN_CTX *ctx; +int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) { int i,bits,ret=0; - BIGNUM *v,*tmp; + BIGNUM *v,*rr; - v=ctx->bn[ctx->tos++]; - tmp=ctx->bn[ctx->tos++]; + BN_CTX_start(ctx); + if ((r == a) || (r == p)) + rr = BN_CTX_get(ctx); + else + rr = r; + if ((v = BN_CTX_get(ctx)) == 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; } + { if (BN_copy(rr,a) == NULL) goto err; } + else { if (!BN_one(rr)) goto err; } for (i=1; itos-=2; + if (r != rr) BN_copy(r,rr); + BN_CTX_end(ctx); return(ret); } -#endif -int BN_mod_exp(r,a,p,m,ctx) -BIGNUM *r; -BIGNUM *a; -BIGNUM *p; -BIGNUM *m; -BN_CTX *ctx; +int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, + BN_CTX *ctx) { int ret; + bn_check_top(a); + bn_check_top(p); + bn_check_top(m); + + /* For even modulus m = 2^k*m_odd, it might make sense to compute + * a^p mod m_odd and a^p mod 2^k separately (with Montgomery + * exponentiation for the odd part), using appropriate exponent + * reductions, and combine the results using the CRT. + * + * For now, we use Montgomery only if the modulus is odd; otherwise, + * exponentiation using the reciprocal-based quick remaindering + * algorithm is used. + * + * (Timing obtained with expspeed.c [computations a^p mod m + * where a, p, m are of the same length: 256, 512, 1024, 2048, + * 4096, 8192 bits], compared to the running time of the + * standard algorithm: + * + * BN_mod_exp_mont 33 .. 40 % [AMD K6-2, Linux, debug configuration] + * 55 .. 77 % [UltraSparc processor, but + * debug-solaris-sparcv8-gcc conf.] + * + * BN_mod_exp_recp 50 .. 70 % [AMD K6-2, Linux, debug configuration] + * 62 .. 118 % [UltraSparc, debug-solaris-sparcv8-gcc] + * + * On the Sparc, BN_mod_exp_recp was faster than BN_mod_exp_mont + * at 2048 and more bits, but at 512 and 1024 bits, it was + * slower even than the standard algorithm! + * + * "Real" timings [linux-elf, solaris-sparcv9-gcc configurations] + * should be obtained when the new Montgomery reduction code + * has been integrated into OpenSSL.) + */ + +#define MONT_MUL_MOD +#define MONT_EXP_WORD +#define RECP_MUL_MOD + #ifdef MONT_MUL_MOD /* I have finally been able to take out this pre-condition of * the top bit being set. It was caused by an error in BN_div @@ -137,7 +202,17 @@ 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); } + { +# ifdef MONT_EXP_WORD + if (a->top == 1 && !a->neg) + { + BN_ULONG A = a->d[0]; + ret=BN_mod_exp_mont_word(r,A,p,m,ctx,NULL); + } + else +# endif + ret=BN_mod_exp_mont(r,a,p,m,ctx,NULL); + } else #endif #ifdef RECP_MUL_MOD @@ -149,55 +224,65 @@ BN_CTX *ctx; return(ret); } -/* #ifdef RECP_MUL_MOD */ -int BN_mod_exp_recp(r,a,p,m,ctx) -BIGNUM *r; -BIGNUM *a; -BIGNUM *p; -BIGNUM *m; -BN_CTX *ctx; + +int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, + const BIGNUM *m, BN_CTX *ctx) { - int nb,i,j,bits,ret=0,wstart,wend,window,wvalue; - int start=1; - BIGNUM *d,*aa; - BIGNUM *val[16]; + int i,j,bits,ret=0,wstart,wend,window,wvalue; + int start=1,ts=0; + BIGNUM *aa; + BIGNUM val[TABLE_SIZE]; + BN_RECP_CTX recp; - d=ctx->bn[ctx->tos++]; - aa=ctx->bn[ctx->tos++]; bits=BN_num_bits(p); if (bits == 0) { - BN_one(r); - return(1); + ret = BN_one(r); + return ret; + } + + BN_CTX_start(ctx); + if ((aa = BN_CTX_get(ctx)) == NULL) goto err; + + BN_RECP_CTX_init(&recp); + if (m->neg) + { + /* ignore sign of 'm' */ + if (!BN_copy(aa, m)) goto err; + aa->neg = 0; + if (BN_RECP_CTX_set(&recp,aa,ctx) <= 0) goto err; } - nb=BN_reciprocal(d,m,ctx); - if (nb == -1) goto err; - - val[0]=BN_new(); - if (!BN_mod(val[0],a,m,ctx)) goto err; /* 1 */ - if (!BN_mod_mul_reciprocal(aa,val[0],val[0],m,d,nb,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; + { + if (BN_RECP_CTX_set(&recp,m,ctx) <= 0) goto err; + } - j=1<<(window-1); - for (i=1; i 1) + { + if (!BN_mod_mul_reciprocal(aa,&(val[0]),&(val[0]),&recp,ctx)) + goto err; /* 2 */ + j=1<<(window-1); + for (i=1; i>1],m,d,nb,ctx)) + if (!BN_mod_mul_reciprocal(r,r,&(val[wvalue>>1]),&recp,ctx)) goto err; /* move the 'window' down further */ @@ -258,75 +343,86 @@ BN_CTX *ctx; } ret=1; err: - ctx->tos-=2; - for (i=0; i<16; i++) - if (val[i] != NULL) BN_clear_free(val[i]); + BN_CTX_end(ctx); + for (i=0; id[0] & 1)) { BNerr(BN_F_BN_MOD_EXP_MONT,BN_R_CALLED_WITH_EVEN_MODULUS); return(0); } - d=ctx->bn[ctx->tos++]; bits=BN_num_bits(p); if (bits == 0) { - BN_one(r); - return(1); + ret = BN_one(rr); + return ret; } + BN_CTX_start(ctx); + d = BN_CTX_get(ctx); + r = BN_CTX_get(ctx); + if (d == NULL || r == NULL) goto err; + /* 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 (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; + } - val[0]=BN_new(); - if (BN_ucmp(a,m) >= 0) + BN_init(&val[0]); + ts=1; + if (a->neg || BN_ucmp(a,m) >= 0) { - BN_mod(val[0],a,m,ctx); - aa=val[0]; + if (!BN_nnmod(&(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 <= 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; + if (BN_is_zero(aa)) + { + ret = BN_zero(rr); + goto err; + } + if (!BN_to_montgomery(&(val[0]),aa,mont,ctx)) goto err; /* 1 */ - j=1<<(window-1); - for (i=1; i 1) { - val[i]=BN_new(); - 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>1],mont,ctx)) + if (!BN_mod_mul_montgomery(r,r,&(val[wvalue>>1]),mont,ctx)) goto err; /* move the 'window' down further */ @@ -385,62 +483,201 @@ BN_CTX *ctx; start=0; if (wstart < 0) break; } - BN_from_montgomery(r,r,mont,ctx); + if (!BN_from_montgomery(rr,r,mont,ctx)) goto err; ret=1; err: - if (mont != NULL) BN_MONT_CTX_free(mont); - ctx->tos--; - for (i=0; i<16; i++) - if (val[i] != NULL) BN_clear_free(val[i]); + if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); + BN_CTX_end(ctx); + for (i=0; itop == 0 || !(m->d[0] & 1)) + { + BNerr(BN_F_BN_MOD_EXP_MONT_WORD,BN_R_CALLED_WITH_EVEN_MODULUS); + return(0); + } + if (m->top == 1) + a %= m->d[0]; /* make sure that 'a' is reduced */ + + bits = BN_num_bits(p); + if (bits == 0) + { + ret = BN_one(rr); + return ret; + } + if (a == 0) + { + ret = BN_zero(rr); + return ret; + } + + 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; + + 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(r,a,p,m,ctx) -BIGNUM *r; -BIGNUM *a; -BIGNUM *p; -BIGNUM *m; -BN_CTX *ctx; +int BN_mod_exp_simple(BIGNUM *r, + const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, + BN_CTX *ctx) { - int i,j,bits,ret=0,wstart,wend,window,wvalue; + int i,j,bits,ret=0,wstart,wend,window,wvalue,ts=0; int start=1; BIGNUM *d; - BIGNUM *val[16]; + BIGNUM val[TABLE_SIZE]; - d=ctx->bn[ctx->tos++]; bits=BN_num_bits(p); if (bits == 0) { - BN_one(r); - return(1); + ret = BN_one(r); + return ret; } - val[0]=BN_new(); - 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; + BN_CTX_start(ctx); + if ((d = BN_CTX_get(ctx)) == NULL) goto err; - j=1<<(window-1); - for (i=1; i 1) + { + if (!BN_mod_mul(d,&(val[0]),&(val[0]),m,ctx)) + goto err; /* 2 */ + j=1<<(window-1); + for (i=1; i>1],m,ctx)) + if (!BN_mod_mul(r,r,&(val[wvalue>>1]),m,ctx)) goto err; /* move the 'window' down further */ @@ -502,9 +739,9 @@ BN_CTX *ctx; } ret=1; err: - ctx->tos--; - for (i=0; i<16; i++) - if (val[i] != NULL) BN_clear_free(val[i]); + BN_CTX_end(ctx); + for (i=0; i