diff options
Diffstat (limited to 'crypto/openssl/crypto/bn/bn_exp2.c')
| -rw-r--r-- | crypto/openssl/crypto/bn/bn_exp2.c | 357 |
1 files changed, 229 insertions, 128 deletions
diff --git a/crypto/openssl/crypto/bn/bn_exp2.c b/crypto/openssl/crypto/bn/bn_exp2.c index 4f4e9e3..29029f4 100644 --- a/crypto/openssl/crypto/bn/bn_exp2.c +++ b/crypto/openssl/crypto/bn/bn_exp2.c @@ -1,27 +1,128 @@ +/* crypto/bn/bn_exp2.c */ +/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) + * All rights reserved. + * + * This package is an SSL implementation written + * by Eric Young (eay@cryptsoft.com). + * The implementation was written so as to conform with Netscapes SSL. + * + * This library is free for commercial and non-commercial use as long as + * the following conditions are aheared to. The following conditions + * apply to all code found in this distribution, be it the RC4, RSA, + * lhash, DES, etc., code; not just the SSL code. The SSL documentation + * included with this distribution is covered by the same copyright terms + * except that the holder is Tim Hudson (tjh@cryptsoft.com). + * + * Copyright remains Eric Young's, and as such any Copyright notices in + * the code are not to be removed. + * If this package is used in a product, Eric Young should be given attribution + * as the author of the parts of the library used. + * This can be in the form of a textual message at program startup or + * in documentation (online or textual) provided with the package. + * + * 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 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 acknowledgement: + * "This product includes cryptographic software written by + * Eric Young (eay@cryptsoft.com)" + * The word 'cryptographic' can be left out if the rouines from the library + * being used are not cryptographic related :-). + * 4. If you include any Windows specific code (or a derivative thereof) from + * the apps directory (application code) you must include an acknowledgement: + * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" + * + * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND + * ANY EXPRESS 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 AUTHOR OR 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. + * + * The licence and distribution terms for any publically available version or + * derivative of this code cannot be changed. i.e. this code cannot simply be + * 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" #include "bn_lcl.h" -/* I've done some timing with different table sizes. - * The main hassle is that even with bits set at 3, this requires - * 63 BIGNUMs to store the pre-calculated values. - * 512 1024 - * bits=1 75.4% 79.4% - * bits=2 61.2% 62.4% - * bits=3 61.3% 59.3% - * The lack of speed improvement is also a function of the pre-calculation - * which could be removed. - */ -#define EXP2_TABLE_BITS 2 /* 1 2 3 4 5 */ -#define EXP2_TABLE_SIZE 4 /* 2 4 8 16 32 */ +#define TABLE_SIZE 32 int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2, BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont) { - int i,j,k,bits,bits1,bits2,ret=0,wstart,wend,window,xvalue,yvalue; - int start=1,ts=0,x,y; - BIGNUM *d,*aa1,*aa2,*r; - BIGNUM val[EXP2_TABLE_SIZE][EXP2_TABLE_SIZE]; + int i,j,bits,b,bits1,bits2,ret=0,wpos1,wpos2,window1,window2,wvalue1,wvalue2; + int r_is_one=1,ts1=0,ts2=0; + BIGNUM *d,*r; + BIGNUM *a_mod_m; + BIGNUM val1[TABLE_SIZE], val2[TABLE_SIZE]; BN_MONT_CTX *mont=NULL; bn_check_top(a1); @@ -32,7 +133,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2, if (!(m->d[0] & 1)) { - BNerr(BN_F_BN_MOD_EXP_MONT,BN_R_CALLED_WITH_EVEN_MODULUS); + BNerr(BN_F_BN_MOD_EXP2_MONT,BN_R_CALLED_WITH_EVEN_MODULUS); return(0); } bits1=BN_num_bits(p1); @@ -42,17 +143,13 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2, BN_one(rr); return(1); } + bits=(bits1 > bits2)?bits1:bits2; BN_CTX_start(ctx); d = BN_CTX_get(ctx); r = BN_CTX_get(ctx); if (d == NULL || r == NULL) goto err; - bits=(bits1 > bits2)?bits1:bits2; - - /* If this is not done, things will break in the montgomery - * part */ - if (in_mont != NULL) mont=in_mont; else @@ -61,139 +158,143 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2, if (!BN_MONT_CTX_set(mont,m,ctx)) goto err; } - BN_init(&(val[0][0])); - BN_init(&(val[1][1])); - BN_init(&(val[0][1])); - BN_init(&(val[1][0])); - ts=1; + window1 = BN_window_bits_for_exponent_size(bits1); + window2 = BN_window_bits_for_exponent_size(bits2); + + /* + * Build table for a1: val1[i] := a1^(2*i + 1) mod m for i = 0 .. 2^(window1-1) + */ + BN_init(&val1[0]); + ts1=1; if (BN_ucmp(a1,m) >= 0) { - BN_mod(&(val[1][0]),a1,m,ctx); - aa1= &(val[1][0]); + if (!BN_mod(&(val1[0]),a1,m,ctx)) + goto err; + a_mod_m = &(val1[0]); } else - aa1=a1; + a_mod_m = a1; + if (!BN_to_montgomery(&(val1[0]),a_mod_m,mont,ctx)) goto err; + if (window1 > 1) + { + if (!BN_mod_mul_montgomery(d,&(val1[0]),&(val1[0]),mont,ctx)) goto err; + + j=1<<(window1-1); + for (i=1; i<j; i++) + { + BN_init(&(val1[i])); + if (!BN_mod_mul_montgomery(&(val1[i]),&(val1[i-1]),d,mont,ctx)) + goto err; + } + ts1=i; + } + + + /* + * Build table for a2: val2[i] := a2^(2*i + 1) mod m for i = 0 .. 2^(window2-1) + */ + BN_init(&val2[0]); + ts2=1; if (BN_ucmp(a2,m) >= 0) { - BN_mod(&(val[0][1]),a2,m,ctx); - aa2= &(val[0][1]); + if (!BN_mod(&(val2[0]),a2,m,ctx)) + goto err; + a_mod_m = &(val2[0]); } else - aa2=a2; - if (!BN_to_montgomery(&(val[1][0]),aa1,mont,ctx)) goto err; - if (!BN_to_montgomery(&(val[0][1]),aa2,mont,ctx)) goto err; - if (!BN_mod_mul_montgomery(&(val[1][1]), - &(val[1][0]),&(val[0][1]),mont,ctx)) - goto err; - -#if 0 - if (bits <= 20) /* This is probably 3 or 0x10001, so just do singles */ - window=1; - else if (bits > 250) - window=5; /* max size of window */ - else if (bits >= 120) - window=4; - else - window=3; -#else - window=EXP2_TABLE_BITS; -#endif - - k=1<<window; - for (x=0; x<k; x++) + a_mod_m = a2; + if (!BN_to_montgomery(&(val2[0]),a_mod_m,mont,ctx)) goto err; + if (window2 > 1) { - if (x >= 2) - { - BN_init(&(val[x][0])); - BN_init(&(val[x][1])); - if (!BN_mod_mul_montgomery(&(val[x][0]), - &(val[1][0]),&(val[x-1][0]),mont,ctx)) goto err; - if (!BN_mod_mul_montgomery(&(val[x][1]), - &(val[1][0]),&(val[x-1][1]),mont,ctx)) goto err; - } - for (y=2; y<k; y++) + if (!BN_mod_mul_montgomery(d,&(val2[0]),&(val2[0]),mont,ctx)) goto err; + + j=1<<(window2-1); + for (i=1; i<j; i++) { - BN_init(&(val[x][y])); - if (!BN_mod_mul_montgomery(&(val[x][y]), - &(val[x][y-1]),&(val[0][1]),mont,ctx)) + BN_init(&(val2[i])); + if (!BN_mod_mul_montgomery(&(val2[i]),&(val2[i-1]),d,mont,ctx)) goto err; } + ts2=i; } - ts=k; - - start=1; /* This is used to avoid multiplication etc - * when there is only the value '1' in the - * buffer. */ - xvalue=0; /* The 'x value' of the window */ - yvalue=0; /* The 'y value' of the window */ - 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; - for (;;) + + + /* Now compute the power product, using independent windows. */ + r_is_one=1; + wvalue1=0; /* The 'value' of the first window */ + wvalue2=0; /* The 'value' of the second window */ + wpos1=0; /* If wvalue1 > 0, the bottom bit of the first window */ + wpos2=0; /* If wvalue2 > 0, the bottom bit of the second window */ + + if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err; + for (b=bits-1; b>=0; b--) { - xvalue=BN_is_bit_set(p1,wstart); - yvalue=BN_is_bit_set(p2,wstart); - if (!(xvalue || yvalue)) + if (!r_is_one) { - if (!start) + if (!BN_mod_mul_montgomery(r,r,r,mont,ctx)) + goto err; + } + + if (!wvalue1) + if (BN_is_bit_set(p1, b)) { - if (!BN_mod_mul_montgomery(r,r,r,mont,ctx)) - goto err; + /* consider bits b-window1+1 .. b for this window */ + i = b-window1+1; + while (!BN_is_bit_set(p1, i)) /* works for i<0 */ + i++; + wpos1 = i; + wvalue1 = 1; + for (i = b-1; i >= wpos1; i--) + { + wvalue1 <<= 1; + if (BN_is_bit_set(p1, i)) + wvalue1++; + } } - wstart--; - if (wstart < 0) break; - continue; - } - /* We now have wstart on a 'set' bit, we now need to work out - * how bit a window to do. To do this we need to scan - * forward until the last set bit before the end of the - * window */ - j=wstart; - /* xvalue=BN_is_bit_set(p1,wstart); already set */ - /* yvalue=BN_is_bit_set(p1,wstart); already set */ - wend=0; - for (i=1; i<window; i++) - { - if (wstart-i < 0) break; - xvalue+=xvalue; - xvalue|=BN_is_bit_set(p1,wstart-i); - yvalue+=yvalue; - yvalue|=BN_is_bit_set(p2,wstart-i); - } - - /* i is the size of the current window */ - /* add the 'bytes above' */ - if (!start) - for (j=0; j<i; j++) + + if (!wvalue2) + if (BN_is_bit_set(p2, b)) { - if (!BN_mod_mul_montgomery(r,r,r,mont,ctx)) - goto err; + /* consider bits b-window2+1 .. b for this window */ + i = b-window2+1; + while (!BN_is_bit_set(p2, i)) + i++; + wpos2 = i; + wvalue2 = 1; + for (i = b-1; i >= wpos2; i--) + { + wvalue2 <<= 1; + if (BN_is_bit_set(p2, i)) + wvalue2++; + } } + + if (wvalue1 && b == wpos1) + { + /* wvalue1 is odd and < 2^window1 */ + if (!BN_mod_mul_montgomery(r,r,&(val1[wvalue1>>1]),mont,ctx)) + goto err; + wvalue1 = 0; + r_is_one = 0; + } - /* wvalue will be an odd number < 2^window */ - if (xvalue || yvalue) + if (wvalue2 && b == wpos2) { - if (!BN_mod_mul_montgomery(r,r,&(val[xvalue][yvalue]), - mont,ctx)) goto err; + /* wvalue2 is odd and < 2^window2 */ + if (!BN_mod_mul_montgomery(r,r,&(val2[wvalue2>>1]),mont,ctx)) + goto err; + wvalue2 = 0; + r_is_one = 0; } - - /* move the 'window' down further */ - wstart-=i; - start=0; - if (wstart < 0) break; } BN_from_montgomery(rr,r,mont,ctx); ret=1; err: if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); BN_CTX_end(ctx); - for (i=0; i<ts; i++) - { - for (j=0; j<ts; j++) - { - BN_clear_free(&(val[i][j])); - } - } + for (i=0; i<ts1; i++) + BN_clear_free(&(val1[i])); + for (i=0; i<ts2; i++) + BN_clear_free(&(val2[i])); return(ret); } |
