cbcmac.cpp

#include "pch.h"
 
#ifndef CRYPTOPP_IMPORTS
 
#include "cbcmac.h"
 
NAMESPACE_BEGIN(CryptoPP)
 
void CBC_MAC_Base::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
{
    AccessCipher().SetKey(key, length, params);
    m_reg.CleanNew(AccessCipher().BlockSize());
    m_counter = 0;
}
 
void CBC_MAC_Base::Update(const byte *input, size_t length)
{
    unsigned int blockSize = AccessCipher().BlockSize();
 
    while (m_counter && length)
    {
        m_reg[m_counter++] ^= *input++;
        if (m_counter == blockSize)
            ProcessBuf();
        length--;
    }
 
    if (length >= blockSize)
    {
        size_t leftOver = AccessCipher().AdvancedProcessBlocks(m_reg, input, m_reg, length, BlockTransformation::BT_DontIncrementInOutPointers|BlockTransformation::BT_XorInput);
        input += (length - leftOver);
        length = leftOver;
    }
 
    while (length--)
    {
        m_reg[m_counter++] ^= *input++;
        if (m_counter == blockSize)
            ProcessBuf();
    }
}
 
void CBC_MAC_Base::TruncatedFinal(byte *mac, size_t size)
{
    ThrowIfInvalidTruncatedSize(size);
 
    if (m_counter)
        ProcessBuf();
 
    std::memcpy(mac, m_reg, size);
    std::memset(m_reg, 0, AccessCipher().BlockSize());
}
 
void CBC_MAC_Base::ProcessBuf()
{
    AccessCipher().ProcessBlock(m_reg);
    m_counter = 0;
}
 
NAMESPACE_END
 
#endif