/*
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* Copyright (C) 2015 Southern Storm Software, Pty Ltd.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#include "AES.h"
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#include "Crypto.h"
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#include <string.h>
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#if defined(CRYPTO_AES_DEFAULT) || defined(CRYPTO_DOC)
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/**
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* \class AES192 AES.h <AES.h>
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* \brief AES block cipher with 192-bit keys.
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*
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* \sa AES128, AES256
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*/
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/**
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* \brief Constructs an AES 192-bit block cipher with no initial key.
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*
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* This constructor must be followed by a call to setKey() before the
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* block cipher can be used for encryption or decryption.
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*/
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AES192::AES192()
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{
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rounds = 12;
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schedule = sched;
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}
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AES192::~AES192()
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{
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clean(sched);
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}
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/**
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* \brief Size of a 192-bit AES key in bytes.
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* \return Always returns 24.
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*/
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size_t AES192::keySize() const
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{
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return 24;
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}
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bool AES192::setKey(const uint8_t *key, size_t len)
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{
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if (len != 24)
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return false;
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// Copy the key itself into the first 24 bytes of the schedule.
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uint8_t *schedule = sched;
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memcpy(schedule, key, 24);
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// Expand the key schedule until we have 208 bytes of expanded key.
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uint8_t iteration = 1;
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uint8_t n = 24;
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uint8_t w = 6;
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while (n < 208) {
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if (w == 6) {
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// Every 24 bytes (6 words) we need to apply the key schedule core.
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keyScheduleCore(schedule + 24, schedule + 20, iteration);
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schedule[24] ^= schedule[0];
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schedule[25] ^= schedule[1];
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schedule[26] ^= schedule[2];
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schedule[27] ^= schedule[3];
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++iteration;
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w = 0;
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} else {
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// Otherwise just XOR the word with the one 24 bytes previous.
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schedule[24] = schedule[20] ^ schedule[0];
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schedule[25] = schedule[21] ^ schedule[1];
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schedule[26] = schedule[22] ^ schedule[2];
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schedule[27] = schedule[23] ^ schedule[3];
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}
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// Advance to the next word in the schedule.
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schedule += 4;
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n += 4;
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++w;
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}
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return true;
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}
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#endif // CRYPTO_AES_DEFAULT
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