57 lines
1.5 KiB
C
57 lines
1.5 KiB
C
/*
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* Crypto wrapper for internal crypto implementation - modexp
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* Copyright (c) 2006-2009, Jouni Malinen <j@w1.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*/
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#include "crypto/includes.h"
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#include "crypto/common.h"
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#include "bignum.h"
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#include "crypto/crypto.h"
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int
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crypto_mod_exp(const u8 *base, size_t base_len,
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const u8 *power, size_t power_len,
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const u8 *modulus, size_t modulus_len,
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u8 *result, size_t *result_len)
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{
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struct bignum *bn_base, *bn_exp, *bn_modulus, *bn_result;
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int ret = -1;
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bn_base = bignum_init();
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bn_exp = bignum_init();
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bn_modulus = bignum_init();
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bn_result = bignum_init();
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if (bn_base == NULL || bn_exp == NULL || bn_modulus == NULL ||
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bn_result == NULL)
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goto error;
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if (bignum_set_unsigned_bin(bn_base, base, base_len) < 0 ||
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bignum_set_unsigned_bin(bn_exp, power, power_len) < 0 ||
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bignum_set_unsigned_bin(bn_modulus, modulus, modulus_len) < 0)
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goto error;
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if (bignum_exptmod(bn_base, bn_exp, bn_modulus, bn_result) < 0)
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goto error;
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ret = bignum_get_unsigned_bin(bn_result, result, result_len);
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error:
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bignum_deinit(bn_base);
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bignum_deinit(bn_exp);
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bignum_deinit(bn_modulus);
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bignum_deinit(bn_result);
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return ret;
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}
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