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| 1 /* crypto/bn/bn_recp.c */ | |
| 2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | |
| 3 * All rights reserved. | |
| 4 * | |
| 5 * This package is an SSL implementation written | |
| 6 * by Eric Young (eay@cryptsoft.com). | |
| 7 * The implementation was written so as to conform with Netscapes SSL. | |
| 8 * | |
| 9 * This library is free for commercial and non-commercial use as long as | |
| 10 * the following conditions are aheared to. The following conditions | |
| 11 * apply to all code found in this distribution, be it the RC4, RSA, | |
| 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation | |
| 13 * included with this distribution is covered by the same copyright terms | |
| 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). | |
| 15 * | |
| 16 * Copyright remains Eric Young's, and as such any Copyright notices in | |
| 17 * the code are not to be removed. | |
| 18 * If this package is used in a product, Eric Young should be given attribution | |
| 19 * as the author of the parts of the library used. | |
| 20 * This can be in the form of a textual message at program startup or | |
| 21 * in documentation (online or textual) provided with the package. | |
| 22 * | |
| 23 * Redistribution and use in source and binary forms, with or without | |
| 24 * modification, are permitted provided that the following conditions | |
| 25 * are met: | |
| 26 * 1. Redistributions of source code must retain the copyright | |
| 27 * notice, this list of conditions and the following disclaimer. | |
| 28 * 2. Redistributions in binary form must reproduce the above copyright | |
| 29 * notice, this list of conditions and the following disclaimer in the | |
| 30 * documentation and/or other materials provided with the distribution. | |
| 31 * 3. All advertising materials mentioning features or use of this software | |
| 32 * must display the following acknowledgement: | |
| 33 * "This product includes cryptographic software written by | |
| 34 * Eric Young (eay@cryptsoft.com)" | |
| 35 * The word 'cryptographic' can be left out if the rouines from the library | |
| 36 * being used are not cryptographic related :-). | |
| 37 * 4. If you include any Windows specific code (or a derivative thereof) from | |
| 38 * the apps directory (application code) you must include an acknowledgement: | |
| 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
| 40 * | |
| 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND | |
| 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
| 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 51 * SUCH DAMAGE. | |
| 52 * | |
| 53 * The licence and distribution terms for any publically available version or | |
| 54 * derivative of this code cannot be changed. i.e. this code cannot simply be | |
| 55 * copied and put under another distribution licence | |
| 56 * [including the GNU Public Licence.] | |
| 57 */ | |
| 58 | |
| 59 #include <stdio.h> | |
| 60 #include "cryptlib.h" | |
| 61 #include "bn_lcl.h" | |
| 62 | |
| 63 void BN_RECP_CTX_init(BN_RECP_CTX *recp) | |
| 64 { | |
| 65 BN_init(&(recp->N)); | |
| 66 BN_init(&(recp->Nr)); | |
| 67 recp->num_bits=0; | |
| 68 recp->flags=0; | |
| 69 } | |
| 70 | |
| 71 BN_RECP_CTX *BN_RECP_CTX_new(void) | |
| 72 { | |
| 73 BN_RECP_CTX *ret; | |
| 74 | |
| 75 if ((ret=(BN_RECP_CTX *)OPENSSL_malloc(sizeof(BN_RECP_CTX))) == NULL) | |
| 76 return(NULL); | |
| 77 | |
| 78 BN_RECP_CTX_init(ret); | |
| 79 ret->flags=BN_FLG_MALLOCED; | |
| 80 return(ret); | |
| 81 } | |
| 82 | |
| 83 void BN_RECP_CTX_free(BN_RECP_CTX *recp) | |
| 84 { | |
| 85 if(recp == NULL) | |
| 86 return; | |
| 87 | |
| 88 BN_free(&(recp->N)); | |
| 89 BN_free(&(recp->Nr)); | |
| 90 if (recp->flags & BN_FLG_MALLOCED) | |
| 91 OPENSSL_free(recp); | |
| 92 } | |
| 93 | |
| 94 int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx) | |
| 95 { | |
| 96 if (!BN_copy(&(recp->N),d)) return 0; | |
| 97 BN_zero(&(recp->Nr)); | |
| 98 recp->num_bits=BN_num_bits(d); | |
| 99 recp->shift=0; | |
| 100 return(1); | |
| 101 } | |
| 102 | |
| 103 int BN_mod_mul_reciprocal(BIGNUM *r, const BIGNUM *x, const BIGNUM *y, | |
| 104 BN_RECP_CTX *recp, BN_CTX *ctx) | |
| 105 { | |
| 106 int ret=0; | |
| 107 BIGNUM *a; | |
| 108 const BIGNUM *ca; | |
| 109 | |
| 110 BN_CTX_start(ctx); | |
| 111 if ((a = BN_CTX_get(ctx)) == NULL) goto err; | |
| 112 if (y != NULL) | |
| 113 { | |
| 114 if (x == y) | |
| 115 { if (!BN_sqr(a,x,ctx)) goto err; } | |
| 116 else | |
| 117 { if (!BN_mul(a,x,y,ctx)) goto err; } | |
| 118 ca = a; | |
| 119 } | |
| 120 else | |
| 121 ca=x; /* Just do the mod */ | |
| 122 | |
| 123 ret = BN_div_recp(NULL,r,ca,recp,ctx); | |
| 124 err: | |
| 125 BN_CTX_end(ctx); | |
| 126 bn_check_top(r); | |
| 127 return(ret); | |
| 128 } | |
| 129 | |
| 130 int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, | |
| 131 BN_RECP_CTX *recp, BN_CTX *ctx) | |
| 132 { | |
| 133 int i,j,ret=0; | |
| 134 BIGNUM *a,*b,*d,*r; | |
| 135 | |
| 136 BN_CTX_start(ctx); | |
| 137 a=BN_CTX_get(ctx); | |
| 138 b=BN_CTX_get(ctx); | |
| 139 if (dv != NULL) | |
| 140 d=dv; | |
| 141 else | |
| 142 d=BN_CTX_get(ctx); | |
| 143 if (rem != NULL) | |
| 144 r=rem; | |
| 145 else | |
| 146 r=BN_CTX_get(ctx); | |
| 147 if (a == NULL || b == NULL || d == NULL || r == NULL) goto err; | |
| 148 | |
| 149 if (BN_ucmp(m,&(recp->N)) < 0) | |
| 150 { | |
| 151 BN_zero(d); | |
| 152 if (!BN_copy(r,m)) return 0; | |
| 153 BN_CTX_end(ctx); | |
| 154 return(1); | |
| 155 } | |
| 156 | |
| 157 /* We want the remainder | |
| 158 * Given input of ABCDEF / ab | |
| 159 * we need multiply ABCDEF by 3 digests of the reciprocal of ab | |
| 160 * | |
| 161 */ | |
| 162 | |
| 163 /* i := max(BN_num_bits(m), 2*BN_num_bits(N)) */ | |
| 164 i=BN_num_bits(m); | |
| 165 j=recp->num_bits<<1; | |
| 166 if (j>i) i=j; | |
| 167 | |
| 168 /* Nr := round(2^i / N) */ | |
| 169 if (i != recp->shift) | |
| 170 recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N), | |
| 171 i,ctx); /* BN_reciprocal returns i, or -1 for an error *
/ | |
| 172 if (recp->shift == -1) goto err; | |
| 173 | |
| 174 /* d := |round(round(m / 2^BN_num_bits(N)) * recp->Nr / 2^(i - BN_num_bi
ts(N)))| | |
| 175 * = |round(round(m / 2^BN_num_bits(N)) * round(2^i / N) / 2^(i - BN_
num_bits(N)))| | |
| 176 * <= |(m / 2^BN_num_bits(N)) * (2^i / N) * (2^BN_num_bits(N) / 2^i)| | |
| 177 * = |m/N| | |
| 178 */ | |
| 179 if (!BN_rshift(a,m,recp->num_bits)) goto err; | |
| 180 if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err; | |
| 181 if (!BN_rshift(d,b,i-recp->num_bits)) goto err; | |
| 182 d->neg=0; | |
| 183 | |
| 184 if (!BN_mul(b,&(recp->N),d,ctx)) goto err; | |
| 185 if (!BN_usub(r,m,b)) goto err; | |
| 186 r->neg=0; | |
| 187 | |
| 188 #if 1 | |
| 189 j=0; | |
| 190 while (BN_ucmp(r,&(recp->N)) >= 0) | |
| 191 { | |
| 192 if (j++ > 2) | |
| 193 { | |
| 194 BNerr(BN_F_BN_DIV_RECP,BN_R_BAD_RECIPROCAL); | |
| 195 goto err; | |
| 196 } | |
| 197 if (!BN_usub(r,r,&(recp->N))) goto err; | |
| 198 if (!BN_add_word(d,1)) goto err; | |
| 199 } | |
| 200 #endif | |
| 201 | |
| 202 r->neg=BN_is_zero(r)?0:m->neg; | |
| 203 d->neg=m->neg^recp->N.neg; | |
| 204 ret=1; | |
| 205 err: | |
| 206 BN_CTX_end(ctx); | |
| 207 bn_check_top(dv); | |
| 208 bn_check_top(rem); | |
| 209 return(ret); | |
| 210 } | |
| 211 | |
| 212 /* len is the expected size of the result | |
| 213 * We actually calculate with an extra word of precision, so | |
| 214 * we can do faster division if the remainder is not required. | |
| 215 */ | |
| 216 /* r := 2^len / m */ | |
| 217 int BN_reciprocal(BIGNUM *r, const BIGNUM *m, int len, BN_CTX *ctx) | |
| 218 { | |
| 219 int ret= -1; | |
| 220 BIGNUM *t; | |
| 221 | |
| 222 BN_CTX_start(ctx); | |
| 223 if((t = BN_CTX_get(ctx)) == NULL) goto err; | |
| 224 | |
| 225 if (!BN_set_bit(t,len)) goto err; | |
| 226 | |
| 227 if (!BN_div(r,NULL,t,m,ctx)) goto err; | |
| 228 | |
| 229 ret=len; | |
| 230 err: | |
| 231 bn_check_top(r); | |
| 232 BN_CTX_end(ctx); | |
| 233 return(ret); | |
| 234 } | |
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Chromium Code Reviews
Issue 2072073002:
Delete bundled copy of OpenSSL and replace with README. (Closed)
Base URL: https://chromium.googlesource.com/chromium/deps/openssl@master