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();

        memcpy(mac, m_reg, size);
        memset(m_reg, 0, AccessCipher().BlockSize());
}

void CBC_MAC_Base::ProcessBuf()
{
        AccessCipher().ProcessBlock(m_reg);
        m_counter = 0;
}

NAMESPACE_END

#endif