// strciphr.cpp - written and placed in the public domain by Wei Dai#include "pch.h"#include "strciphr.h"NAMESPACE_BEGIN(CryptoPP)template <class S>byte AdditiveCipherTemplate<S>::GenerateByte(){	PolicyInterface &policy = AccessPolicy();	if (m_leftOver == 0)	{		policy.WriteKeystream(m_buffer, policy.GetIterationsToBuffer());		m_leftOver = policy.GetBytesPerIteration();	}	return *(KeystreamBufferEnd()-m_leftOver--);}template <class S>inline void AdditiveCipherTemplate<S>::ProcessData(byte *outString, const byte *inString, unsigned int length){	if (m_leftOver > 0)	{		unsigned int len = STDMIN(m_leftOver, length);		xorbuf(outString, inString, KeystreamBufferEnd()-m_leftOver, len);		length -= len;		m_leftOver -= len;		inString += len;		outString += len;	}	if (!length)		return;	assert(m_leftOver == 0);	PolicyInterface &policy = AccessPolicy();	unsigned int bytesPerIteration = policy.GetBytesPerIteration();	unsigned int alignment = policy.GetAlignment();	if (policy.CanOperateKeystream() && length >= bytesPerIteration && IsAlignedOn(outString, alignment))	{		if (IsAlignedOn(inString, alignment))			policy.OperateKeystream(XOR_KEYSTREAM, outString, inString, length / bytesPerIteration);		else		{			memcpy(outString, inString, length);			policy.OperateKeystream(XOR_KEYSTREAM_INPLACE, outString, outString, length / bytesPerIteration);		}		inString += length - length % bytesPerIteration;		outString += length - length % bytesPerIteration;		length %= bytesPerIteration;		if (!length)			return;	}	unsigned int bufferByteSize = GetBufferByteSize(policy);	unsigned int bufferIterations = policy.GetIterationsToBuffer();	while (length >= bufferByteSize)	{		policy.WriteKeystream(m_buffer, bufferIterations);		xorbuf(outString, inString, KeystreamBufferBegin(), bufferByteSize);		length -= bufferByteSize;		inString += bufferByteSize;		outString += bufferByteSize;	}	if (length > 0)	{		policy.WriteKeystream(m_buffer, bufferIterations);		xorbuf(outString, inString, KeystreamBufferBegin(), length);		m_leftOver = bytesPerIteration - length;	}}template <class S>void AdditiveCipherTemplate<S>::Resynchronize(const byte *iv){	PolicyInterface &policy = AccessPolicy();	m_leftOver = 0;	m_buffer.New(GetBufferByteSize(policy));	policy.CipherResynchronize(m_buffer, iv);}template <class BASE>void AdditiveCipherTemplate<BASE>::Seek(dword position){	PolicyInterface &policy = AccessPolicy();	unsigned int bytesPerIteration = policy.GetBytesPerIteration();	policy.SeekToIteration(position / bytesPerIteration);	position %= bytesPerIteration;	if (position > 0)	{		policy.WriteKeystream(m_buffer, 1);		m_leftOver = bytesPerIteration - (unsigned int)position;	}	else		m_leftOver = 0;}template <class BASE>void CFB_CipherTemplate<BASE>::Resynchronize(const byte *iv){	PolicyInterface &policy = AccessPolicy();	policy.CipherResynchronize(iv);	m_leftOver = policy.GetBytesPerIteration();}template <class BASE>void CFB_CipherTemplate<BASE>::ProcessData(byte *outString, const byte *inString, unsigned int length){	PolicyInterface &policy = AccessPolicy();	unsigned int bytesPerIteration = policy.GetBytesPerIteration();	unsigned int alignment = policy.GetAlignment();	byte *reg = policy.GetRegisterBegin();	if (m_leftOver)	{		unsigned int len = STDMIN(m_leftOver, length);		CombineMessageAndShiftRegister(outString, reg + bytesPerIteration - m_leftOver, inString, len);		m_leftOver -= len;		length -= len;		inString += len;		outString += len;	}	if (!length)		return;	assert(m_leftOver == 0);	if (policy.CanIterate() && length >= bytesPerIteration && IsAlignedOn(outString, alignment))	{		if (IsAlignedOn(inString, alignment))			policy.Iterate(outString, inString, GetCipherDir(*this), length / bytesPerIteration);		else		{			memcpy(outString, inString, length);			policy.Iterate(outString, outString, GetCipherDir(*this), length / bytesPerIteration);		}		inString += length - length % bytesPerIteration;		outString += length - length % bytesPerIteration;		length %= bytesPerIteration;	}	while (length >= bytesPerIteration)	{		policy.TransformRegister();		CombineMessageAndShiftRegister(outString, reg, inString, bytesPerIteration);		length -= bytesPerIteration;		inString += bytesPerIteration;		outString += bytesPerIteration;	}	if (length > 0)	{		policy.TransformRegister();		CombineMessageAndShiftRegister(outString, reg, inString, length);		m_leftOver = bytesPerIteration - length;	}}template <class BASE>void CFB_EncryptionTemplate<BASE>::CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, unsigned int length){	xorbuf(reg, message, length);	memcpy(output, reg, length);}template <class BASE>void CFB_DecryptionTemplate<BASE>::CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, unsigned int length){	for (unsigned int i=0; i<length; i++)	{		byte b = message[i];		output[i] = reg[i] ^ b;		reg[i] = b;	}}NAMESPACE_END