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379 lines
12 KiB
379 lines
12 KiB
/* crypto/dsa/dsa_gen.c */ |
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
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* All rights reserved. |
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* |
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* This package is an SSL implementation written |
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* by Eric Young (eay@cryptsoft.com). |
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* The implementation was written so as to conform with Netscapes SSL. |
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* |
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* This library is free for commercial and non-commercial use as long as |
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* the following conditions are aheared to. The following conditions |
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* apply to all code found in this distribution, be it the RC4, RSA, |
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation |
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* included with this distribution is covered by the same copyright terms |
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* except that the holder is Tim Hudson (tjh@cryptsoft.com). |
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* |
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* Copyright remains Eric Young's, and as such any Copyright notices in |
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* the code are not to be removed. |
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* If this package is used in a product, Eric Young should be given attribution |
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* as the author of the parts of the library used. |
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* This can be in the form of a textual message at program startup or |
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* in documentation (online or textual) provided with the package. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* "This product includes cryptographic software written by |
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* Eric Young (eay@cryptsoft.com)" |
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* The word 'cryptographic' can be left out if the rouines from the library |
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* being used are not cryptographic related :-). |
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* 4. If you include any Windows specific code (or a derivative thereof) from |
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* the apps directory (application code) you must include an acknowledgement: |
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* The licence and distribution terms for any publically available version or |
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* derivative of this code cannot be changed. i.e. this code cannot simply be |
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* copied and put under another distribution licence |
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* [including the GNU Public Licence.] |
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*/ |
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#undef GENUINE_DSA |
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#ifdef GENUINE_DSA |
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/* |
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* Parameter generation follows the original release of FIPS PUB 186, |
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* Appendix 2.2 (i.e. use SHA as defined in FIPS PUB 180) |
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*/ |
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# define HASH EVP_sha() |
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#else |
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/* |
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* Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186, |
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* also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB |
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* 180-1) |
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*/ |
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# define HASH EVP_sha1() |
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#endif |
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#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */ |
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#ifndef OPENSSL_NO_SHA |
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# include <stdio.h> |
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# include "cryptlib.h" |
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# include <openssl/evp.h> |
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# include <openssl/bn.h> |
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# include <openssl/rand.h> |
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# include <openssl/sha.h> |
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# include "dsa_locl.h" |
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# ifdef OPENSSL_FIPS |
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# include <openssl/fips.h> |
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# endif |
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int DSA_generate_parameters_ex(DSA *ret, int bits, |
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const unsigned char *seed_in, int seed_len, |
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int *counter_ret, unsigned long *h_ret, |
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BN_GENCB *cb) |
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{ |
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# ifdef OPENSSL_FIPS |
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if (FIPS_mode() && !(ret->meth->flags & DSA_FLAG_FIPS_METHOD) |
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&& !(ret->flags & DSA_FLAG_NON_FIPS_ALLOW)) { |
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DSAerr(DSA_F_DSA_GENERATE_PARAMETERS_EX, DSA_R_NON_FIPS_DSA_METHOD); |
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return 0; |
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} |
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# endif |
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if (ret->meth->dsa_paramgen) |
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return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len, |
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counter_ret, h_ret, cb); |
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# ifdef OPENSSL_FIPS |
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else if (FIPS_mode()) { |
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return FIPS_dsa_generate_parameters_ex(ret, bits, |
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seed_in, seed_len, |
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counter_ret, h_ret, cb); |
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} |
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# endif |
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else { |
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const EVP_MD *evpmd = bits >= 2048 ? EVP_sha256() : EVP_sha1(); |
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size_t qbits = EVP_MD_size(evpmd) * 8; |
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return dsa_builtin_paramgen(ret, bits, qbits, evpmd, |
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seed_in, seed_len, NULL, counter_ret, |
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h_ret, cb); |
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} |
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} |
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int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits, |
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const EVP_MD *evpmd, const unsigned char *seed_in, |
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size_t seed_len, unsigned char *seed_out, |
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int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) |
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{ |
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int ok = 0; |
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unsigned char seed[SHA256_DIGEST_LENGTH]; |
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unsigned char md[SHA256_DIGEST_LENGTH]; |
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unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH]; |
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BIGNUM *r0, *W, *X, *c, *test; |
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BIGNUM *g = NULL, *q = NULL, *p = NULL; |
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BN_MONT_CTX *mont = NULL; |
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int i, k, n = 0, m = 0, qsize = qbits >> 3; |
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int counter = 0; |
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int r = 0; |
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BN_CTX *ctx = NULL; |
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unsigned int h = 2; |
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if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH && |
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qsize != SHA256_DIGEST_LENGTH) |
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/* invalid q size */ |
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return 0; |
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if (evpmd == NULL) |
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/* use SHA1 as default */ |
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evpmd = EVP_sha1(); |
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if (bits < 512) |
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bits = 512; |
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bits = (bits + 63) / 64 * 64; |
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/* |
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* NB: seed_len == 0 is special case: copy generated seed to seed_in if |
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* it is not NULL. |
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*/ |
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if (seed_len && (seed_len < (size_t)qsize)) |
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seed_in = NULL; /* seed buffer too small -- ignore */ |
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if (seed_len > (size_t)qsize) |
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seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger |
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* SEED, but our internal buffers are |
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* restricted to 160 bits */ |
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if (seed_in != NULL) |
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memcpy(seed, seed_in, seed_len); |
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if ((mont = BN_MONT_CTX_new()) == NULL) |
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goto err; |
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if ((ctx = BN_CTX_new()) == NULL) |
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goto err; |
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BN_CTX_start(ctx); |
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r0 = BN_CTX_get(ctx); |
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g = BN_CTX_get(ctx); |
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W = BN_CTX_get(ctx); |
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q = BN_CTX_get(ctx); |
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X = BN_CTX_get(ctx); |
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c = BN_CTX_get(ctx); |
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p = BN_CTX_get(ctx); |
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test = BN_CTX_get(ctx); |
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if (!BN_lshift(test, BN_value_one(), bits - 1)) |
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goto err; |
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for (;;) { |
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for (;;) { /* find q */ |
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int seed_is_random; |
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/* step 1 */ |
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if (!BN_GENCB_call(cb, 0, m++)) |
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goto err; |
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if (!seed_len || !seed_in) { |
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if (RAND_bytes(seed, qsize) <= 0) |
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goto err; |
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seed_is_random = 1; |
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} else { |
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seed_is_random = 0; |
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seed_len = 0; /* use random seed if 'seed_in' turns out to |
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* be bad */ |
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} |
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memcpy(buf, seed, qsize); |
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memcpy(buf2, seed, qsize); |
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/* precompute "SEED + 1" for step 7: */ |
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for (i = qsize - 1; i >= 0; i--) { |
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buf[i]++; |
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if (buf[i] != 0) |
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break; |
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} |
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/* step 2 */ |
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if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL)) |
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goto err; |
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if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL)) |
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goto err; |
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for (i = 0; i < qsize; i++) |
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md[i] ^= buf2[i]; |
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/* step 3 */ |
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md[0] |= 0x80; |
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md[qsize - 1] |= 0x01; |
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if (!BN_bin2bn(md, qsize, q)) |
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goto err; |
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/* step 4 */ |
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r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, |
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seed_is_random, cb); |
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if (r > 0) |
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break; |
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if (r != 0) |
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goto err; |
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/* do a callback call */ |
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/* step 5 */ |
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} |
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if (!BN_GENCB_call(cb, 2, 0)) |
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goto err; |
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if (!BN_GENCB_call(cb, 3, 0)) |
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goto err; |
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/* step 6 */ |
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counter = 0; |
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/* "offset = 2" */ |
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n = (bits - 1) / 160; |
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for (;;) { |
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if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) |
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goto err; |
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/* step 7 */ |
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BN_zero(W); |
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/* now 'buf' contains "SEED + offset - 1" */ |
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for (k = 0; k <= n; k++) { |
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/* |
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* obtain "SEED + offset + k" by incrementing: |
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*/ |
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for (i = qsize - 1; i >= 0; i--) { |
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buf[i]++; |
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if (buf[i] != 0) |
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break; |
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} |
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if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL)) |
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goto err; |
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/* step 8 */ |
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if (!BN_bin2bn(md, qsize, r0)) |
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goto err; |
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if (!BN_lshift(r0, r0, (qsize << 3) * k)) |
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goto err; |
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if (!BN_add(W, W, r0)) |
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goto err; |
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} |
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/* more of step 8 */ |
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if (!BN_mask_bits(W, bits - 1)) |
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goto err; |
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if (!BN_copy(X, W)) |
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goto err; |
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if (!BN_add(X, X, test)) |
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goto err; |
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/* step 9 */ |
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if (!BN_lshift1(r0, q)) |
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goto err; |
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if (!BN_mod(c, X, r0, ctx)) |
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goto err; |
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if (!BN_sub(r0, c, BN_value_one())) |
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goto err; |
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if (!BN_sub(p, X, r0)) |
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goto err; |
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/* step 10 */ |
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if (BN_cmp(p, test) >= 0) { |
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/* step 11 */ |
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r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb); |
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if (r > 0) |
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goto end; /* found it */ |
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if (r != 0) |
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goto err; |
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} |
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/* step 13 */ |
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counter++; |
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/* "offset = offset + n + 1" */ |
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/* step 14 */ |
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if (counter >= 4096) |
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break; |
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} |
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} |
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end: |
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if (!BN_GENCB_call(cb, 2, 1)) |
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goto err; |
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/* We now need to generate g */ |
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/* Set r0=(p-1)/q */ |
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if (!BN_sub(test, p, BN_value_one())) |
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goto err; |
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if (!BN_div(r0, NULL, test, q, ctx)) |
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goto err; |
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if (!BN_set_word(test, h)) |
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goto err; |
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if (!BN_MONT_CTX_set(mont, p, ctx)) |
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goto err; |
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for (;;) { |
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/* g=test^r0%p */ |
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if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont)) |
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goto err; |
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if (!BN_is_one(g)) |
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break; |
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if (!BN_add(test, test, BN_value_one())) |
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goto err; |
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h++; |
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} |
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if (!BN_GENCB_call(cb, 3, 1)) |
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goto err; |
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ok = 1; |
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err: |
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if (ok) { |
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if (ret->p) |
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BN_free(ret->p); |
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if (ret->q) |
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BN_free(ret->q); |
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if (ret->g) |
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BN_free(ret->g); |
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ret->p = BN_dup(p); |
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ret->q = BN_dup(q); |
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ret->g = BN_dup(g); |
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if (ret->p == NULL || ret->q == NULL || ret->g == NULL) { |
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ok = 0; |
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goto err; |
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} |
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if (counter_ret != NULL) |
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*counter_ret = counter; |
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if (h_ret != NULL) |
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*h_ret = h; |
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if (seed_out) |
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memcpy(seed_out, seed, qsize); |
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} |
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if (ctx) { |
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BN_CTX_end(ctx); |
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BN_CTX_free(ctx); |
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} |
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if (mont != NULL) |
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BN_MONT_CTX_free(mont); |
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return ok; |
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} |
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#endif
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