99 lines
1.9 KiB
C
99 lines
1.9 KiB
C
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/*
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* Copyright (C) 2015 Martin Willi
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* Copyright (C) 2015 revosec AG
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include "aesni_key.h"
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/**
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* Rounds used for each AES key size
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*/
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#define AES128_ROUNDS 10
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typedef struct private_aesni_key_t private_aesni_key_t;
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/**
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* Private data of an aesni_key_t object.
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*/
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struct private_aesni_key_t {
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/**
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* Public aesni_key_t interface.
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*/
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aesni_key_t public;
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};
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/**
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* Invert round encryption keys to get a decryption key schedule
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*/
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static void reverse_key(aesni_key_t *this)
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{
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__m128i t[this->rounds + 1];
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int i;
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for (i = 0; i <= this->rounds; i++)
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{
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t[i] = this->schedule[i];
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}
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this->schedule[this->rounds] = t[0];
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for (i = 1; i < this->rounds; i++)
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{
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this->schedule[this->rounds - i] = _mm_aesimc_si128(t[i]);
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}
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this->schedule[0] = t[this->rounds];
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memwipe(t, sizeof(t));
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}
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METHOD(aesni_key_t, destroy, void,
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private_aesni_key_t *this)
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{
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memwipe(this, sizeof(*this) + (this->public.rounds + 1) * AES_BLOCK_SIZE);
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free(this);
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}
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/**
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* See header
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*/
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aesni_key_t *aesni_key_create(bool encrypt, chunk_t key)
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{
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private_aesni_key_t *this;
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int rounds;
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switch (key.len)
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{
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default:
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return NULL;
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}
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INIT_EXTRA(this, (rounds + 1) * AES_BLOCK_SIZE,
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.public = {
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.destroy = _destroy,
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.rounds = rounds,
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},
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);
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switch (key.len)
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{
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default:
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break;
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}
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if (!encrypt)
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{
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reverse_key(&this->public);
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}
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return &this->public;
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}
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