/* $OpenBSD: bn_mod_exp.c,v 1.11 2022/12/08 07:18:47 tb Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include #include #include #include #include "bn_local.h" #define NUM_BITS (BN_BITS*2) #define INIT_MOD_EXP_FN(f) { .name = #f, .mod_exp_fn = (f), } #define INIT_MOD_EXP_MONT_FN(f) { .name = #f, .mod_exp_mont_fn = (f), } static const struct mod_exp_test { const char *name; int (*mod_exp_fn)(BIGNUM *,const BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *); int (*mod_exp_mont_fn)(BIGNUM *,const BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *, BN_MONT_CTX *); } mod_exp_fn[] = { INIT_MOD_EXP_FN(BN_mod_exp), INIT_MOD_EXP_FN(BN_mod_exp_ct), INIT_MOD_EXP_FN(BN_mod_exp_nonct), INIT_MOD_EXP_FN(BN_mod_exp_recp), INIT_MOD_EXP_MONT_FN(BN_mod_exp_mont), INIT_MOD_EXP_MONT_FN(BN_mod_exp_mont_ct), INIT_MOD_EXP_MONT_FN(BN_mod_exp_mont_consttime), INIT_MOD_EXP_MONT_FN(BN_mod_exp_mont_nonct), }; #define N_MOD_EXP_FN (sizeof(mod_exp_fn) / sizeof(mod_exp_fn[0])) static int test_mod_exp(const BIGNUM *result_simple, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, BN_CTX *ctx, const struct mod_exp_test *test) { BIGNUM *result; int ret = 0; BN_CTX_start(ctx); if ((result = BN_CTX_get(ctx)) == NULL) goto err; if (test->mod_exp_fn != NULL) { if (!test->mod_exp_fn(result, a, b, m, ctx)) { printf("%s() problems\n", test->name); goto err; } } else { if (!test->mod_exp_mont_fn(result, a, b, m, ctx, NULL)) { printf("%s() problems\n", test->name); goto err; } } if (BN_cmp(result_simple, result) != 0) { printf("\nResults from BN_mod_exp_simple and %s differ\n", test->name); printf("a (%3d) = ", BN_num_bits(a)); BN_print_fp(stdout, a); printf("\nb (%3d) = ", BN_num_bits(b)); BN_print_fp(stdout, b); printf("\nm (%3d) = ", BN_num_bits(m)); BN_print_fp(stdout, m); printf("\nsimple = "); BN_print_fp(stdout, result_simple); printf("\nresult = "); BN_print_fp(stdout, result); printf("\n"); goto err; } ret = 1; err: BN_CTX_end(ctx); return ret; } int main(int argc, char *argv[]) { BIGNUM *result_simple, *a, *b, *m; BN_CTX *ctx; int c, i; size_t j; if ((ctx = BN_CTX_new()) == NULL) goto err; BN_CTX_start(ctx); if ((a = BN_CTX_get(ctx)) == NULL) goto err; if ((b = BN_CTX_get(ctx)) == NULL) goto err; if ((m = BN_CTX_get(ctx)) == NULL) goto err; if ((result_simple = BN_CTX_get(ctx)) == NULL) goto err; for (i = 0; i < 200; i++) { c = arc4random() % BN_BITS - BN_BITS2; if (!BN_rand(a, NUM_BITS + c, 0, 0)) goto err; c = arc4random() % BN_BITS - BN_BITS2; if (!BN_rand(b, NUM_BITS + c, 0, 0)) goto err; c = arc4random() % BN_BITS - BN_BITS2; if (!BN_rand(m, NUM_BITS + c, 0, 1)) goto err; if (!BN_mod(a, a, m, ctx)) goto err; if (!BN_mod(b, b, m, ctx)) goto err; if ((BN_mod_exp_simple(result_simple, a, b, m, ctx)) <= 0) { printf("BN_mod_exp_simple() problems\n"); goto err; } for (j = 0; j < N_MOD_EXP_FN; j++) { const struct mod_exp_test *test = &mod_exp_fn[j]; if (!test_mod_exp(result_simple, a, b, m, ctx, test)) goto err; } } BN_CTX_end(ctx); BN_CTX_free(ctx); return 0; err: BN_CTX_end(ctx); BN_CTX_free(ctx); ERR_print_errors_fp(stdout); return 1; }