86 lines
2.4 KiB
C++
86 lines
2.4 KiB
C++
/*
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* File: RijndaelCBCMAC.cpp
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*
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* Copyright (c) Freescale Semiconductor, Inc. All rights reserved.
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* See included license file for license details.
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*/
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#include "RijndaelCBCMAC.h"
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#include "rijndael.h"
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#include <assert.h>
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#include "Logging.h"
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void logHexArray(Logger::log_level_t level, const uint8_t *bytes, unsigned count);
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//! \param key The key to use as the CBC-MAC secret.
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//! \param iv Initialization vector. Defaults to zero if not provided.
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RijndaelCBCMAC::RijndaelCBCMAC(const AESKey<128> &key, const uint8_t *iv)
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: m_key(key)
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{
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if (iv)
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{
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memcpy(m_mac, iv, sizeof(m_mac));
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}
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else
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{
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memset(m_mac, 0, sizeof(m_mac));
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}
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}
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//! \param data Pointer to data to process.
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//! \param length Number of bytes to process. Must be evenly divisible by #BLOCK_SIZE.
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void RijndaelCBCMAC::update(const uint8_t *data, unsigned length)
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{
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assert(length % BLOCK_SIZE == 0);
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unsigned blocks = length / BLOCK_SIZE;
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while (blocks--)
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{
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updateOneBlock(data);
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data += BLOCK_SIZE;
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}
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}
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//! It appears that some forms of CBC-MAC encrypt the final output block again in
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//! order to protect against a plaintext attack. This method is a placeholder for
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//! such an operation, but it currently does nothing.
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void RijndaelCBCMAC::finalize()
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{
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}
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//! On entry the current value of m_mac becomes the initialization vector
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//! for the CBC encryption of this block. The output of the encryption then
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//! becomes the new MAC, which is stored in m_mac.
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void RijndaelCBCMAC::updateOneBlock(const uint8_t *data)
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{
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Rijndael cipher;
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cipher.init(Rijndael::CBC, Rijndael::Encrypt, m_key, Rijndael::Key16Bytes, m_mac);
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cipher.blockEncrypt(data, BLOCK_SIZE * 8, m_mac); // size is in bits
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// Log::log(Logger::DEBUG2, "CBC-MAC output block:\n");
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// logHexArray(Logger::DEBUG2, (const uint8_t *)&m_mac, sizeof(m_mac));
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}
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/*!
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* \brief Log an array of bytes as hex.
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*/
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void logHexArray(Logger::log_level_t level, const uint8_t *bytes, unsigned count)
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{
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Log::SetOutputLevel leveler(level);
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// Log::log(" ");
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unsigned i;
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for (i = 0; i < count; ++i, ++bytes)
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{
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if ((i % 16 == 0) && (i < count - 1))
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{
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if (i != 0)
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{
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Log::log("\n");
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}
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Log::log(" 0x%04x: ", i);
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}
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Log::log("%02x ", *bytes & 0xff);
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}
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Log::log("\n");
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}
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