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/*
* CBC-MAC
* (C) 1999-2007 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/cbc_mac.h>
#include <botan/internal/xor_buf.h>
#include <algorithm>
namespace Botan {
/*
* Update an CBC-MAC Calculation
*/
void CBC_MAC::add_data(const byte input[], u32bit length)
{
u32bit xored = std::min(OUTPUT_LENGTH - position, length);
xor_buf(&state[position], input, xored);
position += xored;
if(position < OUTPUT_LENGTH)
return;
e->encrypt(state);
input += xored;
length -= xored;
while(length >= OUTPUT_LENGTH)
{
xor_buf(state, input, OUTPUT_LENGTH);
e->encrypt(state);
input += OUTPUT_LENGTH;
length -= OUTPUT_LENGTH;
}
xor_buf(state, input, length);
position = length;
}
/*
* Finalize an CBC-MAC Calculation
*/
void CBC_MAC::final_result(byte mac[])
{
if(position)
e->encrypt(state);
copy_mem(mac, &state[0], state.size());
zeroise(state);
position = 0;
}
/*
* CBC-MAC Key Schedule
*/
void CBC_MAC::key_schedule(const byte key[], u32bit length)
{
e->set_key(key, length);
}
/*
* Clear memory of sensitive data
*/
void CBC_MAC::clear()
{
e->clear();
zeroise(state);
position = 0;
}
/*
* Return the name of this type
*/
std::string CBC_MAC::name() const
{
return "CBC-MAC(" + e->name() + ")";
}
/*
* Return a clone of this object
*/
MessageAuthenticationCode* CBC_MAC::clone() const
{
return new CBC_MAC(e->clone());
}
/*
* CBC-MAC Constructor
*/
CBC_MAC::CBC_MAC(BlockCipher* e_in) :
MessageAuthenticationCode(e_in->BLOCK_SIZE,
e_in->MINIMUM_KEYLENGTH,
e_in->MAXIMUM_KEYLENGTH,
e_in->KEYLENGTH_MULTIPLE),
e(e_in), state(e->BLOCK_SIZE)
{
position = 0;
}
/*
* CBC-MAC Destructor
*/
CBC_MAC::~CBC_MAC()
{
delete e;
}
}
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