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external/crypto++-5.6.3/strciphr.cpp

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+// strciphr.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+
+#ifndef CRYPTOPP_IMPORTS
+
+#include "strciphr.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+template <class S>
+void AdditiveCipherTemplate<S>::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
+{
+	PolicyInterface &policy = this->AccessPolicy();
+	policy.CipherSetKey(params, key, length);
+	m_leftOver = 0;
+	unsigned int bufferByteSize = policy.CanOperateKeystream() ? GetBufferByteSize(policy) : RoundUpToMultipleOf(1024U, GetBufferByteSize(policy));
+	m_buffer.New(bufferByteSize);
+
+	if (this->IsResynchronizable())
+	{
+		size_t ivLength;
+		const byte *iv = this->GetIVAndThrowIfInvalid(params, ivLength);
+		policy.CipherResynchronize(m_buffer, iv, ivLength);
+	}
+}
+
+template <class S>
+void AdditiveCipherTemplate<S>::GenerateBlock(byte *outString, size_t length)
+{
+	if (m_leftOver > 0)
+	{
+		size_t len = STDMIN(m_leftOver, length);
+		memcpy(outString, KeystreamBufferEnd()-m_leftOver, len);
+		length -= len;
+		m_leftOver -= len;
+		outString += len;
+
+		if (!length)
+			return;
+	}
+	assert(m_leftOver == 0);
+
+	PolicyInterface &policy = this->AccessPolicy();
+	unsigned int bytesPerIteration = policy.GetBytesPerIteration();
+
+	if (length >= bytesPerIteration)
+	{
+		size_t iterations = length / bytesPerIteration;
+		policy.WriteKeystream(outString, iterations);
+		outString += iterations * bytesPerIteration;
+		length -= iterations * bytesPerIteration;
+	}
+
+	if (length > 0)
+	{
+		size_t bufferByteSize = RoundUpToMultipleOf(length, bytesPerIteration);
+		size_t bufferIterations = bufferByteSize / bytesPerIteration;
+
+		policy.WriteKeystream(KeystreamBufferEnd()-bufferByteSize, bufferIterations);
+		memcpy(outString, KeystreamBufferEnd()-bufferByteSize, length);
+		m_leftOver = bufferByteSize - length;
+	}
+}
+
+template <class S>
+void AdditiveCipherTemplate<S>::ProcessData(byte *outString, const byte *inString, size_t length)
+{
+	if (m_leftOver > 0)
+	{
+		size_t 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 = this->AccessPolicy();
+	unsigned int bytesPerIteration = policy.GetBytesPerIteration();
+
+	if (policy.CanOperateKeystream() && length >= bytesPerIteration)
+	{
+		size_t iterations = length / bytesPerIteration;
+		unsigned int alignment = policy.GetAlignment();
+		KeystreamOperation operation = KeystreamOperation((IsAlignedOn(inString, alignment) * 2) | (int)IsAlignedOn(outString, alignment));
+
+		policy.OperateKeystream(operation, outString, inString, iterations);
+
+		inString += iterations * bytesPerIteration;
+		outString += iterations * bytesPerIteration;
+		length -= iterations * bytesPerIteration;
+
+		if (!length)
+			return;
+	}
+
+	size_t bufferByteSize = m_buffer.size();
+	size_t bufferIterations = bufferByteSize / bytesPerIteration;
+
+	while (length >= bufferByteSize)
+	{
+		policy.WriteKeystream(m_buffer, bufferIterations);
+		xorbuf(outString, inString, KeystreamBufferBegin(), bufferByteSize);
+		length -= bufferByteSize;
+		inString += bufferByteSize;
+		outString += bufferByteSize;
+	}
+
+	if (length > 0)
+	{
+		bufferByteSize = RoundUpToMultipleOf(length, bytesPerIteration);
+		bufferIterations = bufferByteSize / bytesPerIteration;
+
+		policy.WriteKeystream(KeystreamBufferEnd()-bufferByteSize, bufferIterations);
+		xorbuf(outString, inString, KeystreamBufferEnd()-bufferByteSize, length);
+		m_leftOver = bufferByteSize - length;
+	}
+}
+
+template <class S>
+void AdditiveCipherTemplate<S>::Resynchronize(const byte *iv, int length)
+{
+	PolicyInterface &policy = this->AccessPolicy();
+	m_leftOver = 0;
+	m_buffer.New(GetBufferByteSize(policy));
+	policy.CipherResynchronize(m_buffer, iv, this->ThrowIfInvalidIVLength(length));
+}
+
+template <class BASE>
+void AdditiveCipherTemplate<BASE>::Seek(lword position)
+{
+	PolicyInterface &policy = this->AccessPolicy();
+	unsigned int bytesPerIteration = policy.GetBytesPerIteration();
+
+	policy.SeekToIteration(position / bytesPerIteration);
+	position %= bytesPerIteration;
+
+	if (position > 0)
+	{
+		policy.WriteKeystream(KeystreamBufferEnd()-bytesPerIteration, 1);
+		m_leftOver = bytesPerIteration - (unsigned int)position;
+	}
+	else
+		m_leftOver = 0;
+}
+
+template <class BASE>
+void CFB_CipherTemplate<BASE>::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
+{
+	PolicyInterface &policy = this->AccessPolicy();
+	policy.CipherSetKey(params, key, length);
+
+	if (this->IsResynchronizable())
+	{
+		size_t ivLength;
+		const byte *iv = this->GetIVAndThrowIfInvalid(params, ivLength);
+		policy.CipherResynchronize(iv, ivLength);
+	}
+
+	m_leftOver = policy.GetBytesPerIteration();
+}
+
+template <class BASE>
+void CFB_CipherTemplate<BASE>::Resynchronize(const byte *iv, int length)
+{
+	PolicyInterface &policy = this->AccessPolicy();
+	policy.CipherResynchronize(iv, this->ThrowIfInvalidIVLength(length));
+	m_leftOver = policy.GetBytesPerIteration();
+}
+
+template <class BASE>
+void CFB_CipherTemplate<BASE>::ProcessData(byte *outString, const byte *inString, size_t length)
+{
+	assert(length % this->MandatoryBlockSize() == 0);
+
+	PolicyInterface &policy = this->AccessPolicy();
+	unsigned int bytesPerIteration = policy.GetBytesPerIteration();
+	unsigned int alignment = policy.GetAlignment();
+	byte *reg = policy.GetRegisterBegin();
+
+	if (m_leftOver)
+	{
+		size_t 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, size_t length)
+{
+	xorbuf(reg, message, length);
+	memcpy(output, reg, length);
+}
+
+template <class BASE>
+void CFB_DecryptionTemplate<BASE>::CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, size_t length)
+{
+	for (unsigned int i=0; i<length; i++)
+	{
+		byte b = message[i];
+		output[i] = reg[i] ^ b;
+		reg[i] = b;
+	}
+}
+
+NAMESPACE_END
+
+#endif