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/*
* Crypto wrapper for internal crypto implementation - modexp
* Copyright (c) 2006-2009, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "tls/bignum.h"
#include "crypto.h"
int crypto_mod_exp(const u8 *base, size_t base_len,
const u8 *power, size_t power_len,
const u8 *modulus, size_t modulus_len,
u8 *result, size_t *result_len)
{
struct bignum *bn_base, *bn_exp, *bn_modulus, *bn_result;
int ret = -1;
bn_base = bignum_init();
bn_exp = bignum_init();
bn_modulus = bignum_init();
bn_result = bignum_init();
if (bn_base == NULL || bn_exp == NULL || bn_modulus == NULL ||
bn_result == NULL)
goto error;
if (bignum_set_unsigned_bin(bn_base, base, base_len) < 0 ||
bignum_set_unsigned_bin(bn_exp, power, power_len) < 0 ||
bignum_set_unsigned_bin(bn_modulus, modulus, modulus_len) < 0)
goto error;
if (bignum_exptmod(bn_base, bn_exp, bn_modulus, bn_result) < 0)
goto error;
ret = bignum_get_unsigned_bin(bn_result, result, result_len);
error:
bignum_deinit(bn_base);
bignum_deinit(bn_exp);
bignum_deinit(bn_modulus);
bignum_deinit(bn_result);
return ret;
}
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