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/*
* ANSI X9.19 MAC
* (C) 1999-2007 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/x919_mac.h>
#include <botan/internal/xor_buf.h>
#include <algorithm>
namespace Botan {
/*
* Update an ANSI X9.19 MAC Calculation
*/
void ANSI_X919_MAC::add_data(const byte input[], size_t length)
{
size_t xored = std::min(8 - m_position, length);
xor_buf(&m_state[m_position], input, xored);
m_position += xored;
if(m_position < 8) return;
m_des1->encrypt(m_state);
input += xored;
length -= xored;
while(length >= 8)
{
xor_buf(m_state, input, 8);
m_des1->encrypt(m_state);
input += 8;
length -= 8;
}
xor_buf(m_state, input, length);
m_position = length;
}
/*
* Finalize an ANSI X9.19 MAC Calculation
*/
void ANSI_X919_MAC::final_result(byte mac[])
{
if(m_position)
m_des1->encrypt(m_state);
m_des2->decrypt(&m_state[0], mac);
m_des1->encrypt(mac);
zeroise(m_state);
m_position = 0;
}
/*
* ANSI X9.19 MAC Key Schedule
*/
void ANSI_X919_MAC::key_schedule(const byte key[], size_t length)
{
m_des1->set_key(key, 8);
if(length == 16)
key += 8;
m_des2->set_key(key, 8);
}
/*
* Clear memory of sensitive data
*/
void ANSI_X919_MAC::clear()
{
m_des1->clear();
m_des2->clear();
zeroise(m_state);
m_position = 0;
}
std::string ANSI_X919_MAC::name() const
{
return "X9.19-MAC";
}
MessageAuthenticationCode* ANSI_X919_MAC::clone() const
{
return new ANSI_X919_MAC(m_des1->clone());
}
/*
* ANSI X9.19 MAC Constructor
*/
ANSI_X919_MAC::ANSI_X919_MAC(BlockCipher* cipher) :
m_des1(cipher), m_des2(m_des1->clone()), m_state(8), m_position(0)
{
if(cipher->name() != "DES")
throw Invalid_Argument("ANSI X9.19 MAC only supports DES");
}
}
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