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#ifndef CRYPTOPP_CBCMAC_H
#define CRYPTOPP_CBCMAC_H
#include "seckey.h"
#include "secblock.h"
NAMESPACE_BEGIN(CryptoPP)
template <class T>
class CBC_MAC_Base : public SameKeyLengthAs<T>, public MessageAuthenticationCode
{
public:
static std::string StaticAlgorithmName() {return std::string("CBC-MAC(") + T::StaticAlgorithmName() + ")";}
CBC_MAC_Base() {}
void CheckedSetKey(void *, Empty empty, const byte *key, unsigned int length, const NameValuePairs ¶ms);
void Update(const byte *input, unsigned int length);
void TruncatedFinal(byte *mac, unsigned int size);
unsigned int DigestSize() const {return m_cipher.BlockSize();}
private:
void ProcessBuf();
typename T::Encryption m_cipher;
SecByteBlock m_reg;
unsigned int m_counter;
};
//! <a href="http://www.weidai.com/scan-mirror/mac.html#CBC-MAC">CBC-MAC</a>
/*! Compatible with FIPS 113. T should be an encryption class.
Secure only for fixed length messages. For variable length
messages use DMAC.
*/
template <class T>
class CBC_MAC : public MessageAuthenticationCodeTemplate<CBC_MAC_Base<T> >
{
public:
CBC_MAC() {}
CBC_MAC(const byte *key, unsigned int length=CBC_MAC_Base<T>::DEFAULT_KEYLENGTH)
{SetKey(key, length);}
};
template <class T>
void CBC_MAC_Base<T>::CheckedSetKey(void *, Empty empty, const byte *key, unsigned int length, const NameValuePairs ¶ms)
{
m_cipher.SetKey(key, length, params);
m_reg.CleanNew(m_cipher.BlockSize());
m_counter = 0;
}
template <class T>
void CBC_MAC_Base<T>::Update(const byte *input, unsigned int length)
{
while (m_counter && length)
{
m_reg[m_counter++] ^= *input++;
if (m_counter == T::BLOCKSIZE)
ProcessBuf();
length--;
}
while (length >= T::BLOCKSIZE)
{
xorbuf(m_reg, input, T::BLOCKSIZE);
ProcessBuf();
input += T::BLOCKSIZE;
length -= T::BLOCKSIZE;
}
while (length--)
{
m_reg[m_counter++] ^= *input++;
if (m_counter == T::BLOCKSIZE)
ProcessBuf();
}
}
template <class T>
void CBC_MAC_Base<T>::TruncatedFinal(byte *mac, unsigned int size)
{
ThrowIfInvalidTruncatedSize(size);
if (m_counter)
ProcessBuf();
memcpy(mac, m_reg, size);
memset(m_reg, 0, T::BLOCKSIZE);
}
template <class T>
void CBC_MAC_Base<T>::ProcessBuf()
{
m_cipher.ProcessBlock(m_reg);
m_counter = 0;
}
NAMESPACE_END
#endif
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