workbench/network/WirelessManager/src/crypto/crypto_internal-modexp.c

   1 /*
   2  * Crypto wrapper for internal crypto implementation - modexp
   3  * Copyright (c) 2006-2009, Jouni Malinen <j@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 }