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| 1 /* crypto/bn/bn_sqr.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 /* r must not be a */ | |
| 64 /* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */ | |
| 65 int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) | |
| 66 { | |
| 67 int max,al; | |
| 68 int ret = 0; | |
| 69 BIGNUM *tmp,*rr; | |
| 70 | |
| 71 #ifdef BN_COUNT | |
| 72 fprintf(stderr,"BN_sqr %d * %d\n",a->top,a->top); | |
| 73 #endif | |
| 74 bn_check_top(a); | |
| 75 | |
| 76 al=a->top; | |
| 77 if (al <= 0) | |
| 78 { | |
| 79 r->top=0; | |
| 80 return 1; | |
| 81 } | |
| 82 | |
| 83 BN_CTX_start(ctx); | |
| 84 rr=(a != r) ? r : BN_CTX_get(ctx); | |
| 85 tmp=BN_CTX_get(ctx); | |
| 86 if (!rr || !tmp) goto err; | |
| 87 | |
| 88 max = 2 * al; /* Non-zero (from above) */ | |
| 89 if (bn_wexpand(rr,max) == NULL) goto err; | |
| 90 | |
| 91 if (al == 4) | |
| 92 { | |
| 93 #ifndef BN_SQR_COMBA | |
| 94 BN_ULONG t[8]; | |
| 95 bn_sqr_normal(rr->d,a->d,4,t); | |
| 96 #else | |
| 97 bn_sqr_comba4(rr->d,a->d); | |
| 98 #endif | |
| 99 } | |
| 100 else if (al == 8) | |
| 101 { | |
| 102 #ifndef BN_SQR_COMBA | |
| 103 BN_ULONG t[16]; | |
| 104 bn_sqr_normal(rr->d,a->d,8,t); | |
| 105 #else | |
| 106 bn_sqr_comba8(rr->d,a->d); | |
| 107 #endif | |
| 108 } | |
| 109 else | |
| 110 { | |
| 111 #if defined(BN_RECURSION) | |
| 112 if (al < BN_SQR_RECURSIVE_SIZE_NORMAL) | |
| 113 { | |
| 114 BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL*2]; | |
| 115 bn_sqr_normal(rr->d,a->d,al,t); | |
| 116 } | |
| 117 else | |
| 118 { | |
| 119 int j,k; | |
| 120 | |
| 121 j=BN_num_bits_word((BN_ULONG)al); | |
| 122 j=1<<(j-1); | |
| 123 k=j+j; | |
| 124 if (al == j) | |
| 125 { | |
| 126 if (bn_wexpand(tmp,k*2) == NULL) goto err; | |
| 127 bn_sqr_recursive(rr->d,a->d,al,tmp->d); | |
| 128 } | |
| 129 else | |
| 130 { | |
| 131 if (bn_wexpand(tmp,max) == NULL) goto err; | |
| 132 bn_sqr_normal(rr->d,a->d,al,tmp->d); | |
| 133 } | |
| 134 } | |
| 135 #else | |
| 136 if (bn_wexpand(tmp,max) == NULL) goto err; | |
| 137 bn_sqr_normal(rr->d,a->d,al,tmp->d); | |
| 138 #endif | |
| 139 } | |
| 140 | |
| 141 rr->neg=0; | |
| 142 /* If the most-significant half of the top word of 'a' is zero, then | |
| 143 * the square of 'a' will max-1 words. */ | |
| 144 if(a->d[al - 1] == (a->d[al - 1] & BN_MASK2l)) | |
| 145 rr->top = max - 1; | |
| 146 else | |
| 147 rr->top = max; | |
| 148 if (rr != r) BN_copy(r,rr); | |
| 149 ret = 1; | |
| 150 err: | |
| 151 bn_check_top(rr); | |
| 152 bn_check_top(tmp); | |
| 153 BN_CTX_end(ctx); | |
| 154 return(ret); | |
| 155 } | |
| 156 | |
| 157 /* tmp must have 2*n words */ | |
| 158 void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp) | |
| 159 { | |
| 160 int i,j,max; | |
| 161 const BN_ULONG *ap; | |
| 162 BN_ULONG *rp; | |
| 163 | |
| 164 max=n*2; | |
| 165 ap=a; | |
| 166 rp=r; | |
| 167 rp[0]=rp[max-1]=0; | |
| 168 rp++; | |
| 169 j=n; | |
| 170 | |
| 171 if (--j > 0) | |
| 172 { | |
| 173 ap++; | |
| 174 rp[j]=bn_mul_words(rp,ap,j,ap[-1]); | |
| 175 rp+=2; | |
| 176 } | |
| 177 | |
| 178 for (i=n-2; i>0; i--) | |
| 179 { | |
| 180 j--; | |
| 181 ap++; | |
| 182 rp[j]=bn_mul_add_words(rp,ap,j,ap[-1]); | |
| 183 rp+=2; | |
| 184 } | |
| 185 | |
| 186 bn_add_words(r,r,r,max); | |
| 187 | |
| 188 /* There will not be a carry */ | |
| 189 | |
| 190 bn_sqr_words(tmp,a,n); | |
| 191 | |
| 192 bn_add_words(r,r,tmp,max); | |
| 193 } | |
| 194 | |
| 195 #ifdef BN_RECURSION | |
| 196 /* r is 2*n words in size, | |
| 197 * a and b are both n words in size. (There's not actually a 'b' here ...) | |
| 198 * n must be a power of 2. | |
| 199 * We multiply and return the result. | |
| 200 * t must be 2*n words in size | |
| 201 * We calculate | |
| 202 * a[0]*b[0] | |
| 203 * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0]) | |
| 204 * a[1]*b[1] | |
| 205 */ | |
| 206 void bn_sqr_recursive(BN_ULONG *r, const BN_ULONG *a, int n2, BN_ULONG *t) | |
| 207 { | |
| 208 int n=n2/2; | |
| 209 int zero,c1; | |
| 210 BN_ULONG ln,lo,*p; | |
| 211 | |
| 212 #ifdef BN_COUNT | |
| 213 fprintf(stderr," bn_sqr_recursive %d * %d\n",n2,n2); | |
| 214 #endif | |
| 215 if (n2 == 4) | |
| 216 { | |
| 217 #ifndef BN_SQR_COMBA | |
| 218 bn_sqr_normal(r,a,4,t); | |
| 219 #else | |
| 220 bn_sqr_comba4(r,a); | |
| 221 #endif | |
| 222 return; | |
| 223 } | |
| 224 else if (n2 == 8) | |
| 225 { | |
| 226 #ifndef BN_SQR_COMBA | |
| 227 bn_sqr_normal(r,a,8,t); | |
| 228 #else | |
| 229 bn_sqr_comba8(r,a); | |
| 230 #endif | |
| 231 return; | |
| 232 } | |
| 233 if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL) | |
| 234 { | |
| 235 bn_sqr_normal(r,a,n2,t); | |
| 236 return; | |
| 237 } | |
| 238 /* r=(a[0]-a[1])*(a[1]-a[0]) */ | |
| 239 c1=bn_cmp_words(a,&(a[n]),n); | |
| 240 zero=0; | |
| 241 if (c1 > 0) | |
| 242 bn_sub_words(t,a,&(a[n]),n); | |
| 243 else if (c1 < 0) | |
| 244 bn_sub_words(t,&(a[n]),a,n); | |
| 245 else | |
| 246 zero=1; | |
| 247 | |
| 248 /* The result will always be negative unless it is zero */ | |
| 249 p= &(t[n2*2]); | |
| 250 | |
| 251 if (!zero) | |
| 252 bn_sqr_recursive(&(t[n2]),t,n,p); | |
| 253 else | |
| 254 memset(&(t[n2]),0,n2*sizeof(BN_ULONG)); | |
| 255 bn_sqr_recursive(r,a,n,p); | |
| 256 bn_sqr_recursive(&(r[n2]),&(a[n]),n,p); | |
| 257 | |
| 258 /* t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero | |
| 259 * r[10] holds (a[0]*b[0]) | |
| 260 * r[32] holds (b[1]*b[1]) | |
| 261 */ | |
| 262 | |
| 263 c1=(int)(bn_add_words(t,r,&(r[n2]),n2)); | |
| 264 | |
| 265 /* t[32] is negative */ | |
| 266 c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2)); | |
| 267 | |
| 268 /* t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1]) | |
| 269 * r[10] holds (a[0]*a[0]) | |
| 270 * r[32] holds (a[1]*a[1]) | |
| 271 * c1 holds the carry bits | |
| 272 */ | |
| 273 c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2)); | |
| 274 if (c1) | |
| 275 { | |
| 276 p= &(r[n+n2]); | |
| 277 lo= *p; | |
| 278 ln=(lo+c1)&BN_MASK2; | |
| 279 *p=ln; | |
| 280 | |
| 281 /* The overflow will stop before we over write | |
| 282 * words we should not overwrite */ | |
| 283 if (ln < (BN_ULONG)c1) | |
| 284 { | |
| 285 do { | |
| 286 p++; | |
| 287 lo= *p; | |
| 288 ln=(lo+1)&BN_MASK2; | |
| 289 *p=ln; | |
| 290 } while (ln == 0); | |
| 291 } | |
| 292 } | |
| 293 } | |
| 294 #endif | |
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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