$search
00001 /* 00002 * Crypto wrapper for internal crypto implementation - modexp 00003 * Copyright (c) 2006-2009, Jouni Malinen <j@w1.fi> 00004 * 00005 * This program is free software; you can redistribute it and/or modify 00006 * it under the terms of the GNU General Public License version 2 as 00007 * published by the Free Software Foundation. 00008 * 00009 * Alternatively, this software may be distributed under the terms of BSD 00010 * license. 00011 * 00012 * See README and COPYING for more details. 00013 */ 00014 00015 #include "includes.h" 00016 00017 #include "common.h" 00018 #include "tls/bignum.h" 00019 #include "crypto.h" 00020 00021 00022 int crypto_mod_exp(const u8 *base, size_t base_len, 00023 const u8 *power, size_t power_len, 00024 const u8 *modulus, size_t modulus_len, 00025 u8 *result, size_t *result_len) 00026 { 00027 struct bignum *bn_base, *bn_exp, *bn_modulus, *bn_result; 00028 int ret = -1; 00029 00030 bn_base = bignum_init(); 00031 bn_exp = bignum_init(); 00032 bn_modulus = bignum_init(); 00033 bn_result = bignum_init(); 00034 00035 if (bn_base == NULL || bn_exp == NULL || bn_modulus == NULL || 00036 bn_result == NULL) 00037 goto error; 00038 00039 if (bignum_set_unsigned_bin(bn_base, base, base_len) < 0 || 00040 bignum_set_unsigned_bin(bn_exp, power, power_len) < 0 || 00041 bignum_set_unsigned_bin(bn_modulus, modulus, modulus_len) < 0) 00042 goto error; 00043 00044 if (bignum_exptmod(bn_base, bn_exp, bn_modulus, bn_result) < 0) 00045 goto error; 00046 00047 ret = bignum_get_unsigned_bin(bn_result, result, result_len); 00048 00049 error: 00050 bignum_deinit(bn_base); 00051 bignum_deinit(bn_exp); 00052 bignum_deinit(bn_modulus); 00053 bignum_deinit(bn_result); 00054 return ret; 00055 }