1 /* 2 * Crypto wrapper for internal crypto implementation - modexp 3 * Copyright (c) 2006-2009, Jouni Malinen <j (at) w1.fi> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * Alternatively, this software may be distributed under the terms of BSD 10 * license. 11 * 12 * See README and COPYING for more details. 13 */ 14 15 #include "includes.h" 16 17 #include "common.h" 18 #include "tls/bignum.h" 19 #include "crypto.h" 20 21 22 int crypto_mod_exp(const u8 *base, size_t base_len, 23 const u8 *power, size_t power_len, 24 const u8 *modulus, size_t modulus_len, 25 u8 *result, size_t *result_len) 26 { 27 struct bignum *bn_base, *bn_exp, *bn_modulus, *bn_result; 28 int ret = -1; 29 30 bn_base = bignum_init(); 31 bn_exp = bignum_init(); 32 bn_modulus = bignum_init(); 33 bn_result = bignum_init(); 34 35 if (bn_base == NULL || bn_exp == NULL || bn_modulus == NULL || 36 bn_result == NULL) 37 goto error; 38 39 if (bignum_set_unsigned_bin(bn_base, base, base_len) < 0 || 40 bignum_set_unsigned_bin(bn_exp, power, power_len) < 0 || 41 bignum_set_unsigned_bin(bn_modulus, modulus, modulus_len) < 0) 42 goto error; 43 44 if (bignum_exptmod(bn_base, bn_exp, bn_modulus, bn_result) < 0) 45 goto error; 46 47 ret = bignum_get_unsigned_bin(bn_result, result, result_len); 48 49 error: 50 bignum_deinit(bn_base); 51 bignum_deinit(bn_exp); 52 bignum_deinit(bn_modulus); 53 bignum_deinit(bn_result); 54 return ret; 55 } 56
