1 | /*
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2 | * WARNING: do not edit!
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3 | * Generated by crypto/bn/bn_prime.pl
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4 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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5 | *
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6 | * Licensed under the OpenSSL license (the "License"). You may not use
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7 | * this file except in compliance with the License. You can obtain a copy
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8 | * in the file LICENSE in the source distribution or at
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9 | * https://www.openssl.org/source/license.html
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10 | */
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11 |
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12 | #include <stdio.h>
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13 | #include <time.h>
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14 | #include "internal/cryptlib.h"
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15 | #include "bn_lcl.h"
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16 |
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17 | /*
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18 | * The quick sieve algorithm approach to weeding out primes is Philip
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19 | * Zimmermann's, as implemented in PGP. I have had a read of his comments
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20 | * and implemented my own version.
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21 | */
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22 | #include "bn_prime.h"
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23 |
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24 | static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
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25 | const BIGNUM *a1_odd, int k, BN_CTX *ctx,
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26 | BN_MONT_CTX *mont);
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27 | static int probable_prime(BIGNUM *rnd, int bits, prime_t *mods);
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28 | static int probable_prime_dh_safe(BIGNUM *rnd, int bits,
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29 | const BIGNUM *add, const BIGNUM *rem,
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30 | BN_CTX *ctx);
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31 |
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32 | static const int prime_offsets[480] = {
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33 | 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83,
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34 | 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163,
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35 | 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 221, 223, 227, 229,
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36 | 233, 239, 241, 247, 251, 257, 263, 269, 271, 277, 281, 283, 289, 293,
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37 | 299, 307, 311, 313, 317, 323, 331, 337, 347, 349, 353, 359, 361, 367,
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38 | 373, 377, 379, 383, 389, 391, 397, 401, 403, 409, 419, 421, 431, 433,
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39 | 437, 439, 443, 449, 457, 461, 463, 467, 479, 481, 487, 491, 493, 499,
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40 | 503, 509, 521, 523, 527, 529, 533, 541, 547, 551, 557, 559, 563, 569,
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41 | 571, 577, 587, 589, 593, 599, 601, 607, 611, 613, 617, 619, 629, 631,
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42 | 641, 643, 647, 653, 659, 661, 667, 673, 677, 683, 689, 691, 697, 701,
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43 | 703, 709, 713, 719, 727, 731, 733, 739, 743, 751, 757, 761, 767, 769,
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44 | 773, 779, 787, 793, 797, 799, 809, 811, 817, 821, 823, 827, 829, 839,
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45 | 841, 851, 853, 857, 859, 863, 871, 877, 881, 883, 887, 893, 899, 901,
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46 | 907, 911, 919, 923, 929, 937, 941, 943, 947, 949, 953, 961, 967, 971,
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47 | 977, 983, 989, 991, 997, 1003, 1007, 1009, 1013, 1019, 1021, 1027, 1031,
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48 | 1033, 1037, 1039, 1049, 1051, 1061, 1063, 1069, 1073, 1079, 1081, 1087,
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49 | 1091, 1093, 1097, 1103, 1109, 1117, 1121, 1123, 1129, 1139, 1147, 1151,
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50 | 1153, 1157, 1159, 1163, 1171, 1181, 1187, 1189, 1193, 1201, 1207, 1213,
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51 | 1217, 1219, 1223, 1229, 1231, 1237, 1241, 1247, 1249, 1259, 1261, 1271,
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52 | 1273, 1277, 1279, 1283, 1289, 1291, 1297, 1301, 1303, 1307, 1313, 1319,
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53 | 1321, 1327, 1333, 1339, 1343, 1349, 1357, 1361, 1363, 1367, 1369, 1373,
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54 | 1381, 1387, 1391, 1399, 1403, 1409, 1411, 1417, 1423, 1427, 1429, 1433,
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55 | 1439, 1447, 1451, 1453, 1457, 1459, 1469, 1471, 1481, 1483, 1487, 1489,
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56 | 1493, 1499, 1501, 1511, 1513, 1517, 1523, 1531, 1537, 1541, 1543, 1549,
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57 | 1553, 1559, 1567, 1571, 1577, 1579, 1583, 1591, 1597, 1601, 1607, 1609,
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58 | 1613, 1619, 1621, 1627, 1633, 1637, 1643, 1649, 1651, 1657, 1663, 1667,
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59 | 1669, 1679, 1681, 1691, 1693, 1697, 1699, 1703, 1709, 1711, 1717, 1721,
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60 | 1723, 1733, 1739, 1741, 1747, 1751, 1753, 1759, 1763, 1769, 1777, 1781,
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61 | 1783, 1787, 1789, 1801, 1807, 1811, 1817, 1819, 1823, 1829, 1831, 1843,
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62 | 1847, 1849, 1853, 1861, 1867, 1871, 1873, 1877, 1879, 1889, 1891, 1901,
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63 | 1907, 1909, 1913, 1919, 1921, 1927, 1931, 1933, 1937, 1943, 1949, 1951,
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64 | 1957, 1961, 1963, 1973, 1979, 1987, 1993, 1997, 1999, 2003, 2011, 2017,
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65 | 2021, 2027, 2029, 2033, 2039, 2041, 2047, 2053, 2059, 2063, 2069, 2071,
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66 | 2077, 2081, 2083, 2087, 2089, 2099, 2111, 2113, 2117, 2119, 2129, 2131,
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67 | 2137, 2141, 2143, 2147, 2153, 2159, 2161, 2171, 2173, 2179, 2183, 2197,
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68 | 2201, 2203, 2207, 2209, 2213, 2221, 2227, 2231, 2237, 2239, 2243, 2249,
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69 | 2251, 2257, 2263, 2267, 2269, 2273, 2279, 2281, 2287, 2291, 2293, 2297,
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70 | 2309, 2311
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71 | };
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72 |
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73 | static const int prime_offset_count = 480;
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74 | static const int prime_multiplier = 2310;
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75 | static const int prime_multiplier_bits = 11; /* 2^|prime_multiplier_bits| <=
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76 | * |prime_multiplier| */
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77 | static const int first_prime_index = 5;
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78 |
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79 | int BN_GENCB_call(BN_GENCB *cb, int a, int b)
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80 | {
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81 | /* No callback means continue */
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82 | if (!cb)
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83 | return 1;
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84 | switch (cb->ver) {
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85 | case 1:
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86 | /* Deprecated-style callbacks */
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87 | if (!cb->cb.cb_1)
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88 | return 1;
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89 | cb->cb.cb_1(a, b, cb->arg);
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90 | return 1;
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91 | case 2:
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92 | /* New-style callbacks */
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93 | return cb->cb.cb_2(a, b, cb);
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94 | default:
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95 | break;
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96 | }
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97 | /* Unrecognised callback type */
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98 | return 0;
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99 | }
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100 |
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101 | int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe,
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102 | const BIGNUM *add, const BIGNUM *rem, BN_GENCB *cb)
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103 | {
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104 | BIGNUM *t;
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105 | int found = 0;
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106 | int i, j, c1 = 0;
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107 | BN_CTX *ctx = NULL;
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108 | prime_t *mods = NULL;
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109 | int checks = BN_prime_checks_for_size(bits);
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110 |
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111 | if (bits < 2) {
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112 | /* There are no prime numbers this small. */
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113 | BNerr(BN_F_BN_GENERATE_PRIME_EX, BN_R_BITS_TOO_SMALL);
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114 | return 0;
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115 | } else if (bits == 2 && safe) {
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116 | /* The smallest safe prime (7) is three bits. */
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117 | BNerr(BN_F_BN_GENERATE_PRIME_EX, BN_R_BITS_TOO_SMALL);
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118 | return 0;
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119 | }
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120 |
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121 | mods = OPENSSL_zalloc(sizeof(*mods) * NUMPRIMES);
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122 | if (mods == NULL)
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123 | goto err;
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124 |
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125 | ctx = BN_CTX_new();
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126 | if (ctx == NULL)
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127 | goto err;
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128 | BN_CTX_start(ctx);
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129 | t = BN_CTX_get(ctx);
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130 | if (!t)
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131 | goto err;
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132 | loop:
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133 | /* make a random number and set the top and bottom bits */
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134 | if (add == NULL) {
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135 | if (!probable_prime(ret, bits, mods))
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136 | goto err;
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137 | } else {
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138 | if (safe) {
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139 | if (!probable_prime_dh_safe(ret, bits, add, rem, ctx))
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140 | goto err;
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141 | } else {
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142 | if (!bn_probable_prime_dh(ret, bits, add, rem, ctx))
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143 | goto err;
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144 | }
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145 | }
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146 |
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147 | if (!BN_GENCB_call(cb, 0, c1++))
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148 | /* aborted */
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149 | goto err;
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150 |
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151 | if (!safe) {
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152 | i = BN_is_prime_fasttest_ex(ret, checks, ctx, 0, cb);
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153 | if (i == -1)
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154 | goto err;
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155 | if (i == 0)
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156 | goto loop;
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157 | } else {
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158 | /*
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159 | * for "safe prime" generation, check that (p-1)/2 is prime. Since a
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160 | * prime is odd, We just need to divide by 2
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161 | */
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162 | if (!BN_rshift1(t, ret))
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163 | goto err;
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164 |
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165 | for (i = 0; i < checks; i++) {
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166 | j = BN_is_prime_fasttest_ex(ret, 1, ctx, 0, cb);
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167 | if (j == -1)
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168 | goto err;
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169 | if (j == 0)
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170 | goto loop;
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171 |
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172 | j = BN_is_prime_fasttest_ex(t, 1, ctx, 0, cb);
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173 | if (j == -1)
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174 | goto err;
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175 | if (j == 0)
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176 | goto loop;
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177 |
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178 | if (!BN_GENCB_call(cb, 2, c1 - 1))
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179 | goto err;
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180 | /* We have a safe prime test pass */
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181 | }
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182 | }
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183 | /* we have a prime :-) */
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184 | found = 1;
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185 | err:
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186 | OPENSSL_free(mods);
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187 | if (ctx != NULL)
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188 | BN_CTX_end(ctx);
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189 | BN_CTX_free(ctx);
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190 | bn_check_top(ret);
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191 | return found;
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192 | }
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193 |
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194 | int BN_is_prime_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
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195 | BN_GENCB *cb)
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196 | {
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197 | return BN_is_prime_fasttest_ex(a, checks, ctx_passed, 0, cb);
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198 | }
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199 |
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200 | int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
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201 | int do_trial_division, BN_GENCB *cb)
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202 | {
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203 | int i, j, ret = -1;
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204 | int k;
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205 | BN_CTX *ctx = NULL;
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206 | BIGNUM *A1, *A1_odd, *check; /* taken from ctx */
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207 | BN_MONT_CTX *mont = NULL;
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208 | const BIGNUM *A = NULL;
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209 |
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210 | if (BN_cmp(a, BN_value_one()) <= 0)
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211 | return 0;
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212 |
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213 | if (checks == BN_prime_checks)
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214 | checks = BN_prime_checks_for_size(BN_num_bits(a));
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215 |
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216 | /* first look for small factors */
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217 | if (!BN_is_odd(a))
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218 | /* a is even => a is prime if and only if a == 2 */
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219 | return BN_is_word(a, 2);
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220 | if (do_trial_division) {
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221 | for (i = 1; i < NUMPRIMES; i++) {
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222 | BN_ULONG mod = BN_mod_word(a, primes[i]);
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223 | if (mod == (BN_ULONG)-1)
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224 | goto err;
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225 | if (mod == 0)
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226 | return 0;
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227 | }
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228 | if (!BN_GENCB_call(cb, 1, -1))
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229 | goto err;
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230 | }
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231 |
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232 | if (ctx_passed != NULL)
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233 | ctx = ctx_passed;
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234 | else if ((ctx = BN_CTX_new()) == NULL)
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235 | goto err;
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236 | BN_CTX_start(ctx);
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237 |
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238 | /* A := abs(a) */
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239 | if (a->neg) {
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240 | BIGNUM *t;
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241 | if ((t = BN_CTX_get(ctx)) == NULL)
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242 | goto err;
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243 | if (BN_copy(t, a) == NULL)
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244 | goto err;
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245 | t->neg = 0;
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246 | A = t;
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247 | } else
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248 | A = a;
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249 | A1 = BN_CTX_get(ctx);
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250 | A1_odd = BN_CTX_get(ctx);
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251 | check = BN_CTX_get(ctx);
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252 | if (check == NULL)
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253 | goto err;
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254 |
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255 | /* compute A1 := A - 1 */
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256 | if (!BN_copy(A1, A))
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257 | goto err;
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258 | if (!BN_sub_word(A1, 1))
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259 | goto err;
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260 | if (BN_is_zero(A1)) {
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261 | ret = 0;
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262 | goto err;
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263 | }
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264 |
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265 | /* write A1 as A1_odd * 2^k */
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266 | k = 1;
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267 | while (!BN_is_bit_set(A1, k))
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268 | k++;
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269 | if (!BN_rshift(A1_odd, A1, k))
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270 | goto err;
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271 |
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272 | /* Montgomery setup for computations mod A */
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273 | mont = BN_MONT_CTX_new();
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274 | if (mont == NULL)
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275 | goto err;
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276 | if (!BN_MONT_CTX_set(mont, A, ctx))
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277 | goto err;
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278 |
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279 | for (i = 0; i < checks; i++) {
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280 | if (!BN_pseudo_rand_range(check, A1))
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281 | goto err;
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282 | if (!BN_add_word(check, 1))
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283 | goto err;
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284 | /* now 1 <= check < A */
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285 |
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286 | j = witness(check, A, A1, A1_odd, k, ctx, mont);
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287 | if (j == -1)
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288 | goto err;
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289 | if (j) {
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290 | ret = 0;
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291 | goto err;
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292 | }
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293 | if (!BN_GENCB_call(cb, 1, i))
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294 | goto err;
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295 | }
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296 | ret = 1;
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297 | err:
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298 | if (ctx != NULL) {
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299 | BN_CTX_end(ctx);
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300 | if (ctx_passed == NULL)
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301 | BN_CTX_free(ctx);
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302 | }
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303 | BN_MONT_CTX_free(mont);
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304 |
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305 | return (ret);
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306 | }
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307 |
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308 | int bn_probable_prime_dh_retry(BIGNUM *rnd, int bits, BN_CTX *ctx)
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309 | {
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310 | int i;
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311 | int ret = 0;
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312 |
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313 | loop:
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314 | if (!BN_rand(rnd, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
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315 | goto err;
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316 |
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317 | /* we now have a random number 'rand' to test. */
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318 |
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319 | for (i = 1; i < NUMPRIMES; i++) {
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320 | /* check that rnd is a prime */
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321 | BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
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322 | if (mod == (BN_ULONG)-1)
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323 | goto err;
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324 | if (mod <= 1) {
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325 | goto loop;
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326 | }
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327 | }
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328 | ret = 1;
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329 |
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330 | err:
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331 | bn_check_top(rnd);
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332 | return (ret);
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333 | }
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334 |
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335 | int bn_probable_prime_dh_coprime(BIGNUM *rnd, int bits, BN_CTX *ctx)
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336 | {
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337 | int i;
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338 | BIGNUM *offset_index;
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339 | BIGNUM *offset_count;
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340 | int ret = 0;
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341 |
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342 | OPENSSL_assert(bits > prime_multiplier_bits);
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343 |
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344 | BN_CTX_start(ctx);
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345 | if ((offset_index = BN_CTX_get(ctx)) == NULL)
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346 | goto err;
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347 | if ((offset_count = BN_CTX_get(ctx)) == NULL)
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348 | goto err;
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349 |
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350 | if (!BN_add_word(offset_count, prime_offset_count))
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351 | goto err;
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352 |
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353 | loop:
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354 | if (!BN_rand(rnd, bits - prime_multiplier_bits,
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355 | BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
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356 | goto err;
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357 | if (BN_is_bit_set(rnd, bits))
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358 | goto loop;
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359 | if (!BN_rand_range(offset_index, offset_count))
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360 | goto err;
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361 |
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362 | if (!BN_mul_word(rnd, prime_multiplier)
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363 | || !BN_add_word(rnd, prime_offsets[BN_get_word(offset_index)]))
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364 | goto err;
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365 |
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366 | /* we now have a random number 'rand' to test. */
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367 |
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368 | /* skip coprimes */
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369 | for (i = first_prime_index; i < NUMPRIMES; i++) {
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370 | /* check that rnd is a prime */
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371 | BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
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372 | if (mod == (BN_ULONG)-1)
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373 | goto err;
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374 | if (mod <= 1)
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375 | goto loop;
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376 | }
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377 | ret = 1;
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378 |
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379 | err:
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380 | BN_CTX_end(ctx);
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381 | bn_check_top(rnd);
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382 | return ret;
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383 | }
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384 |
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385 | static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
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386 | const BIGNUM *a1_odd, int k, BN_CTX *ctx,
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387 | BN_MONT_CTX *mont)
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388 | {
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389 | if (!BN_mod_exp_mont(w, w, a1_odd, a, ctx, mont)) /* w := w^a1_odd mod a */
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390 | return -1;
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391 | if (BN_is_one(w))
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392 | return 0; /* probably prime */
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393 | if (BN_cmp(w, a1) == 0)
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394 | return 0; /* w == -1 (mod a), 'a' is probably prime */
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395 | while (--k) {
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396 | if (!BN_mod_mul(w, w, w, a, ctx)) /* w := w^2 mod a */
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397 | return -1;
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398 | if (BN_is_one(w))
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399 | return 1; /* 'a' is composite, otherwise a previous 'w'
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400 | * would have been == -1 (mod 'a') */
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401 | if (BN_cmp(w, a1) == 0)
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402 | return 0; /* w == -1 (mod a), 'a' is probably prime */
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403 | }
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404 | /*
|
---|
405 | * If we get here, 'w' is the (a-1)/2-th power of the original 'w', and
|
---|
406 | * it is neither -1 nor +1 -- so 'a' cannot be prime
|
---|
407 | */
|
---|
408 | bn_check_top(w);
|
---|
409 | return 1;
|
---|
410 | }
|
---|
411 |
|
---|
412 | static int probable_prime(BIGNUM *rnd, int bits, prime_t *mods)
|
---|
413 | {
|
---|
414 | int i;
|
---|
415 | BN_ULONG delta;
|
---|
416 | BN_ULONG maxdelta = BN_MASK2 - primes[NUMPRIMES - 1];
|
---|
417 | char is_single_word = bits <= BN_BITS2;
|
---|
418 |
|
---|
419 | again:
|
---|
420 | if (!BN_rand(rnd, bits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ODD))
|
---|
421 | return (0);
|
---|
422 | /* we now have a random number 'rnd' to test. */
|
---|
423 | for (i = 1; i < NUMPRIMES; i++) {
|
---|
424 | BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
|
---|
425 | if (mod == (BN_ULONG)-1)
|
---|
426 | return 0;
|
---|
427 | mods[i] = (prime_t) mod;
|
---|
428 | }
|
---|
429 | /*
|
---|
430 | * If bits is so small that it fits into a single word then we
|
---|
431 | * additionally don't want to exceed that many bits.
|
---|
432 | */
|
---|
433 | if (is_single_word) {
|
---|
434 | BN_ULONG size_limit;
|
---|
435 |
|
---|
436 | if (bits == BN_BITS2) {
|
---|
437 | /*
|
---|
438 | * Shifting by this much has undefined behaviour so we do it a
|
---|
439 | * different way
|
---|
440 | */
|
---|
441 | size_limit = ~((BN_ULONG)0) - BN_get_word(rnd);
|
---|
442 | } else {
|
---|
443 | size_limit = (((BN_ULONG)1) << bits) - BN_get_word(rnd) - 1;
|
---|
444 | }
|
---|
445 | if (size_limit < maxdelta)
|
---|
446 | maxdelta = size_limit;
|
---|
447 | }
|
---|
448 | delta = 0;
|
---|
449 | loop:
|
---|
450 | if (is_single_word) {
|
---|
451 | BN_ULONG rnd_word = BN_get_word(rnd);
|
---|
452 |
|
---|
453 | /*-
|
---|
454 | * In the case that the candidate prime is a single word then
|
---|
455 | * we check that:
|
---|
456 | * 1) It's greater than primes[i] because we shouldn't reject
|
---|
457 | * 3 as being a prime number because it's a multiple of
|
---|
458 | * three.
|
---|
459 | * 2) That it's not a multiple of a known prime. We don't
|
---|
460 | * check that rnd-1 is also coprime to all the known
|
---|
461 | * primes because there aren't many small primes where
|
---|
462 | * that's true.
|
---|
463 | */
|
---|
464 | for (i = 1; i < NUMPRIMES && primes[i] < rnd_word; i++) {
|
---|
465 | if ((mods[i] + delta) % primes[i] == 0) {
|
---|
466 | delta += 2;
|
---|
467 | if (delta > maxdelta)
|
---|
468 | goto again;
|
---|
469 | goto loop;
|
---|
470 | }
|
---|
471 | }
|
---|
472 | } else {
|
---|
473 | for (i = 1; i < NUMPRIMES; i++) {
|
---|
474 | /*
|
---|
475 | * check that rnd is not a prime and also that gcd(rnd-1,primes)
|
---|
476 | * == 1 (except for 2)
|
---|
477 | */
|
---|
478 | if (((mods[i] + delta) % primes[i]) <= 1) {
|
---|
479 | delta += 2;
|
---|
480 | if (delta > maxdelta)
|
---|
481 | goto again;
|
---|
482 | goto loop;
|
---|
483 | }
|
---|
484 | }
|
---|
485 | }
|
---|
486 | if (!BN_add_word(rnd, delta))
|
---|
487 | return (0);
|
---|
488 | if (BN_num_bits(rnd) != bits)
|
---|
489 | goto again;
|
---|
490 | bn_check_top(rnd);
|
---|
491 | return (1);
|
---|
492 | }
|
---|
493 |
|
---|
494 | int bn_probable_prime_dh(BIGNUM *rnd, int bits,
|
---|
495 | const BIGNUM *add, const BIGNUM *rem, BN_CTX *ctx)
|
---|
496 | {
|
---|
497 | int i, ret = 0;
|
---|
498 | BIGNUM *t1;
|
---|
499 |
|
---|
500 | BN_CTX_start(ctx);
|
---|
501 | if ((t1 = BN_CTX_get(ctx)) == NULL)
|
---|
502 | goto err;
|
---|
503 |
|
---|
504 | if (!BN_rand(rnd, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
|
---|
505 | goto err;
|
---|
506 |
|
---|
507 | /* we need ((rnd-rem) % add) == 0 */
|
---|
508 |
|
---|
509 | if (!BN_mod(t1, rnd, add, ctx))
|
---|
510 | goto err;
|
---|
511 | if (!BN_sub(rnd, rnd, t1))
|
---|
512 | goto err;
|
---|
513 | if (rem == NULL) {
|
---|
514 | if (!BN_add_word(rnd, 1))
|
---|
515 | goto err;
|
---|
516 | } else {
|
---|
517 | if (!BN_add(rnd, rnd, rem))
|
---|
518 | goto err;
|
---|
519 | }
|
---|
520 |
|
---|
521 | /* we now have a random number 'rand' to test. */
|
---|
522 |
|
---|
523 | loop:
|
---|
524 | for (i = 1; i < NUMPRIMES; i++) {
|
---|
525 | /* check that rnd is a prime */
|
---|
526 | BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
|
---|
527 | if (mod == (BN_ULONG)-1)
|
---|
528 | goto err;
|
---|
529 | if (mod <= 1) {
|
---|
530 | if (!BN_add(rnd, rnd, add))
|
---|
531 | goto err;
|
---|
532 | goto loop;
|
---|
533 | }
|
---|
534 | }
|
---|
535 | ret = 1;
|
---|
536 |
|
---|
537 | err:
|
---|
538 | BN_CTX_end(ctx);
|
---|
539 | bn_check_top(rnd);
|
---|
540 | return (ret);
|
---|
541 | }
|
---|
542 |
|
---|
543 | static int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd,
|
---|
544 | const BIGNUM *rem, BN_CTX *ctx)
|
---|
545 | {
|
---|
546 | int i, ret = 0;
|
---|
547 | BIGNUM *t1, *qadd, *q;
|
---|
548 |
|
---|
549 | bits--;
|
---|
550 | BN_CTX_start(ctx);
|
---|
551 | t1 = BN_CTX_get(ctx);
|
---|
552 | q = BN_CTX_get(ctx);
|
---|
553 | qadd = BN_CTX_get(ctx);
|
---|
554 | if (qadd == NULL)
|
---|
555 | goto err;
|
---|
556 |
|
---|
557 | if (!BN_rshift1(qadd, padd))
|
---|
558 | goto err;
|
---|
559 |
|
---|
560 | if (!BN_rand(q, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
|
---|
561 | goto err;
|
---|
562 |
|
---|
563 | /* we need ((rnd-rem) % add) == 0 */
|
---|
564 | if (!BN_mod(t1, q, qadd, ctx))
|
---|
565 | goto err;
|
---|
566 | if (!BN_sub(q, q, t1))
|
---|
567 | goto err;
|
---|
568 | if (rem == NULL) {
|
---|
569 | if (!BN_add_word(q, 1))
|
---|
570 | goto err;
|
---|
571 | } else {
|
---|
572 | if (!BN_rshift1(t1, rem))
|
---|
573 | goto err;
|
---|
574 | if (!BN_add(q, q, t1))
|
---|
575 | goto err;
|
---|
576 | }
|
---|
577 |
|
---|
578 | /* we now have a random number 'rand' to test. */
|
---|
579 | if (!BN_lshift1(p, q))
|
---|
580 | goto err;
|
---|
581 | if (!BN_add_word(p, 1))
|
---|
582 | goto err;
|
---|
583 |
|
---|
584 | loop:
|
---|
585 | for (i = 1; i < NUMPRIMES; i++) {
|
---|
586 | /* check that p and q are prime */
|
---|
587 | /*
|
---|
588 | * check that for p and q gcd(p-1,primes) == 1 (except for 2)
|
---|
589 | */
|
---|
590 | BN_ULONG pmod = BN_mod_word(p, (BN_ULONG)primes[i]);
|
---|
591 | BN_ULONG qmod = BN_mod_word(q, (BN_ULONG)primes[i]);
|
---|
592 | if (pmod == (BN_ULONG)-1 || qmod == (BN_ULONG)-1)
|
---|
593 | goto err;
|
---|
594 | if (pmod == 0 || qmod == 0) {
|
---|
595 | if (!BN_add(p, p, padd))
|
---|
596 | goto err;
|
---|
597 | if (!BN_add(q, q, qadd))
|
---|
598 | goto err;
|
---|
599 | goto loop;
|
---|
600 | }
|
---|
601 | }
|
---|
602 | ret = 1;
|
---|
603 |
|
---|
604 | err:
|
---|
605 | BN_CTX_end(ctx);
|
---|
606 | bn_check_top(p);
|
---|
607 | return (ret);
|
---|
608 | }
|
---|