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1 /* crypto/dsa/dsa_gen.c */ |
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2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
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3 * All rights reserved. |
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4 * |
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5 * This package is an SSL implementation written |
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6 * by Eric Young (eay@cryptsoft.com). |
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7 * The implementation was written so as to conform with Netscapes SSL. |
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8 * |
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9 * This library is free for commercial and non-commercial use as long as |
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10 * the following conditions are aheared to. The following conditions |
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11 * apply to all code found in this distribution, be it the RC4, RSA, |
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12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation |
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13 * included with this distribution is covered by the same copyright terms |
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14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). |
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15 * |
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16 * Copyright remains Eric Young's, and as such any Copyright notices in |
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17 * the code are not to be removed. |
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18 * If this package is used in a product, Eric Young should be given attribution |
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19 * as the author of the parts of the library used. |
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20 * This can be in the form of a textual message at program startup or |
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21 * in documentation (online or textual) provided with the package. |
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22 * |
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23 * Redistribution and use in source and binary forms, with or without |
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24 * modification, are permitted provided that the following conditions |
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25 * are met: |
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26 * 1. Redistributions of source code must retain the copyright |
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27 * notice, this list of conditions and the following disclaimer. |
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28 * 2. Redistributions in binary form must reproduce the above copyright |
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29 * notice, this list of conditions and the following disclaimer in the |
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30 * documentation and/or other materials provided with the distribution. |
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31 * 3. All advertising materials mentioning features or use of this software |
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32 * must display the following acknowledgement: |
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33 * "This product includes cryptographic software written by |
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34 * Eric Young (eay@cryptsoft.com)" |
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35 * The word 'cryptographic' can be left out if the rouines from the library |
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36 * being used are not cryptographic related :-). |
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37 * 4. If you include any Windows specific code (or a derivative thereof) from |
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38 * the apps directory (application code) you must include an acknowledgement: |
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39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
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40 * |
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41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
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42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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51 * SUCH DAMAGE. |
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52 * |
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53 * The licence and distribution terms for any publically available version or |
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54 * derivative of this code cannot be changed. i.e. this code cannot simply be |
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55 * copied and put under another distribution licence |
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56 * [including the GNU Public Licence.] |
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57 */ |
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58 |
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59 #undef GENUINE_DSA |
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60 |
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61 #ifdef GENUINE_DSA |
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62 /* Parameter generation follows the original release of FIPS PUB 186, |
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63 * Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) */ |
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64 #define HASH EVP_sha() |
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65 #else |
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66 /* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186, |
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67 * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in |
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68 * FIPS PUB 180-1) */ |
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69 #define HASH EVP_sha1() |
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70 #endif |
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71 |
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72 #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */ |
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73 |
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74 #ifndef OPENSSL_NO_SHA |
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75 |
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76 #include <stdio.h> |
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77 #include <time.h> |
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78 #include "cryptlib.h" |
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79 #include <openssl/evp.h> |
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80 #include <openssl/bn.h> |
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81 #include <openssl/dsa.h> |
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82 #include <openssl/rand.h> |
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83 #include <openssl/sha.h> |
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84 |
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85 static int dsa_builtin_paramgen(DSA *ret, int bits, |
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86 unsigned char *seed_in, int seed_len, |
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87 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb); |
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88 |
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89 EXPORT_C int DSA_generate_parameters_ex(DSA *ret, int bits, |
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90 unsigned char *seed_in, int seed_len, |
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91 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) |
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92 { |
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93 if(ret->meth->dsa_paramgen) |
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94 return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len, |
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95 counter_ret, h_ret, cb); |
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96 return dsa_builtin_paramgen(ret, bits, seed_in, seed_len, |
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97 counter_ret, h_ret, cb); |
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98 } |
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99 |
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100 static int dsa_builtin_paramgen(DSA *ret, int bits, |
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101 unsigned char *seed_in, int seed_len, |
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102 int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) |
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103 { |
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104 int ok=0; |
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105 unsigned char seed[SHA_DIGEST_LENGTH]; |
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106 unsigned char md[SHA_DIGEST_LENGTH]; |
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107 unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH]; |
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108 BIGNUM *r0,*W,*X,*c,*test; |
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109 BIGNUM *g=NULL,*q=NULL,*p=NULL; |
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110 BN_MONT_CTX *mont=NULL; |
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111 int k,n=0,i,b,m=0; |
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112 int counter=0; |
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113 int r=0; |
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114 BN_CTX *ctx=NULL; |
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115 unsigned int h=2; |
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116 |
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117 if (bits < 512) bits=512; |
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118 bits=(bits+63)/64*64; |
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119 |
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120 /* NB: seed_len == 0 is special case: copy generated seed to |
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121 * seed_in if it is not NULL. |
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122 */ |
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123 if (seed_len && (seed_len < 20)) |
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124 seed_in = NULL; /* seed buffer too small -- ignore */ |
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125 if (seed_len > 20) |
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126 seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED, |
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127 * but our internal buffers are restricted to 160 bits*/ |
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128 if ((seed_in != NULL) && (seed_len == 20)) |
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129 { |
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130 memcpy(seed,seed_in,seed_len); |
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131 /* set seed_in to NULL to avoid it being copied back */ |
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132 seed_in = NULL; |
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133 } |
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134 |
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135 if ((ctx=BN_CTX_new()) == NULL) goto err; |
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136 |
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137 if ((mont=BN_MONT_CTX_new()) == NULL) goto err; |
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138 |
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139 BN_CTX_start(ctx); |
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140 r0 = BN_CTX_get(ctx); |
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141 g = BN_CTX_get(ctx); |
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142 W = BN_CTX_get(ctx); |
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143 q = BN_CTX_get(ctx); |
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144 X = BN_CTX_get(ctx); |
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145 c = BN_CTX_get(ctx); |
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146 p = BN_CTX_get(ctx); |
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147 test = BN_CTX_get(ctx); |
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148 |
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149 if (!BN_lshift(test,BN_value_one(),bits-1)) |
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150 goto err; |
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151 |
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152 for (;;) |
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153 { |
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154 for (;;) /* find q */ |
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155 { |
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156 int seed_is_random; |
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157 |
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158 /* step 1 */ |
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159 if(!BN_GENCB_call(cb, 0, m++)) |
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160 goto err; |
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161 |
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162 if (!seed_len) |
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163 { |
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164 RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH); |
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165 seed_is_random = 1; |
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166 } |
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167 else |
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168 { |
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169 seed_is_random = 0; |
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170 seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/ |
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171 } |
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172 memcpy(buf,seed,SHA_DIGEST_LENGTH); |
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173 memcpy(buf2,seed,SHA_DIGEST_LENGTH); |
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174 /* precompute "SEED + 1" for step 7: */ |
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175 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) |
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176 { |
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177 buf[i]++; |
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178 if (buf[i] != 0) break; |
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179 } |
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180 |
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181 /* step 2 */ |
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182 EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL); |
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183 EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL); |
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184 for (i=0; i<SHA_DIGEST_LENGTH; i++) |
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185 md[i]^=buf2[i]; |
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186 |
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187 /* step 3 */ |
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188 md[0]|=0x80; |
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189 md[SHA_DIGEST_LENGTH-1]|=0x01; |
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190 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err; |
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191 |
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192 /* step 4 */ |
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193 r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, |
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194 seed_is_random, cb); |
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195 if (r > 0) |
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196 break; |
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197 if (r != 0) |
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198 goto err; |
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199 |
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200 /* do a callback call */ |
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201 /* step 5 */ |
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202 } |
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203 |
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204 if(!BN_GENCB_call(cb, 2, 0)) goto err; |
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205 if(!BN_GENCB_call(cb, 3, 0)) goto err; |
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206 |
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207 /* step 6 */ |
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208 counter=0; |
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209 /* "offset = 2" */ |
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210 |
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211 n=(bits-1)/160; |
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212 b=(bits-1)-n*160; |
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213 |
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214 for (;;) |
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215 { |
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216 if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) |
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217 goto err; |
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218 |
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219 /* step 7 */ |
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220 BN_zero(W); |
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221 /* now 'buf' contains "SEED + offset - 1" */ |
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222 for (k=0; k<=n; k++) |
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223 { |
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224 /* obtain "SEED + offset + k" by incrementing: */ |
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225 for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) |
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226 { |
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227 buf[i]++; |
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228 if (buf[i] != 0) break; |
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229 } |
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230 |
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231 EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL); |
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232 |
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233 /* step 8 */ |
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234 if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0)) |
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235 goto err; |
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236 if (!BN_lshift(r0,r0,160*k)) goto err; |
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237 if (!BN_add(W,W,r0)) goto err; |
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238 } |
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239 |
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240 /* more of step 8 */ |
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241 if (!BN_mask_bits(W,bits-1)) goto err; |
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242 if (!BN_copy(X,W)) goto err; |
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243 if (!BN_add(X,X,test)) goto err; |
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244 |
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245 /* step 9 */ |
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246 if (!BN_lshift1(r0,q)) goto err; |
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247 if (!BN_mod(c,X,r0,ctx)) goto err; |
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248 if (!BN_sub(r0,c,BN_value_one())) goto err; |
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249 if (!BN_sub(p,X,r0)) goto err; |
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250 |
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251 /* step 10 */ |
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252 if (BN_cmp(p,test) >= 0) |
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253 { |
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254 /* step 11 */ |
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255 r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, |
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256 ctx, 1, cb); |
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257 if (r > 0) |
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258 goto end; /* found it */ |
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259 if (r != 0) |
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260 goto err; |
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261 } |
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262 |
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263 /* step 13 */ |
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264 counter++; |
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265 /* "offset = offset + n + 1" */ |
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266 |
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267 /* step 14 */ |
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268 if (counter >= 4096) break; |
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269 } |
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270 } |
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271 end: |
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272 if(!BN_GENCB_call(cb, 2, 1)) |
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273 goto err; |
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274 |
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275 /* We now need to generate g */ |
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276 /* Set r0=(p-1)/q */ |
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277 if (!BN_sub(test,p,BN_value_one())) goto err; |
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278 if (!BN_div(r0,NULL,test,q,ctx)) goto err; |
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279 |
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280 if (!BN_set_word(test,h)) goto err; |
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281 if (!BN_MONT_CTX_set(mont,p,ctx)) goto err; |
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282 |
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283 for (;;) |
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284 { |
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285 /* g=test^r0%p */ |
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286 if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err; |
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287 if (!BN_is_one(g)) break; |
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288 if (!BN_add(test,test,BN_value_one())) goto err; |
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289 h++; |
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290 } |
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291 |
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292 if(!BN_GENCB_call(cb, 3, 1)) |
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293 goto err; |
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294 |
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295 ok=1; |
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296 err: |
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297 if (ok) |
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298 { |
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299 if(ret->p) BN_free(ret->p); |
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300 if(ret->q) BN_free(ret->q); |
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301 if(ret->g) BN_free(ret->g); |
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302 ret->p=BN_dup(p); |
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303 ret->q=BN_dup(q); |
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304 ret->g=BN_dup(g); |
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305 if (ret->p == NULL || ret->q == NULL || ret->g == NULL) |
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306 { |
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307 ok=0; |
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308 goto err; |
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309 } |
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310 if (seed_in != NULL) memcpy(seed_in,seed,20); |
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311 if (counter_ret != NULL) *counter_ret=counter; |
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312 if (h_ret != NULL) *h_ret=h; |
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313 } |
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314 if(ctx) |
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315 { |
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316 BN_CTX_end(ctx); |
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317 BN_CTX_free(ctx); |
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318 } |
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319 if (mont != NULL) BN_MONT_CTX_free(mont); |
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320 return ok; |
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321 } |
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322 #endif |