1 files changed, 245 insertions, 0 deletions

diff --git a/CryptoPP/modes.cpp b/CryptoPP/modes.cpp
new file mode 100644
index 000000000..46332284b
--- /dev/null
+++ b/CryptoPP/modes.cpp
@@ -0,0 +1,245 @@
+// modes.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+
+#ifndef CRYPTOPP_IMPORTS
+
+#include "modes.h"
+
+#ifndef NDEBUG
+#include "des.h"
+#endif
+
+NAMESPACE_BEGIN(CryptoPP)
+
+#ifndef NDEBUG
+void Modes_TestInstantiations()
+{
+	CFB_Mode<DES>::Encryption m0;
+	CFB_Mode<DES>::Decryption m1;
+	OFB_Mode<DES>::Encryption m2;
+	CTR_Mode<DES>::Encryption m3;
+	ECB_Mode<DES>::Encryption m4;
+	CBC_Mode<DES>::Encryption m5;
+}
+#endif
+
+void CFB_ModePolicy::Iterate(byte *output, const byte *input, CipherDir dir, size_t iterationCount)
+{
+	assert(m_cipher->IsForwardTransformation());	// CFB mode needs the "encrypt" direction of the underlying block cipher, even to decrypt
+	assert(m_feedbackSize == BlockSize());
+
+	unsigned int s = BlockSize();
+	if (dir == ENCRYPTION)
+	{
+		m_cipher->ProcessAndXorBlock(m_register, input, output);
+		m_cipher->AdvancedProcessBlocks(output, input+s, output+s, (iterationCount-1)*s, 0);
+		memcpy(m_register, output+(iterationCount-1)*s, s);
+	}
+	else
+	{
+		memcpy(m_temp, input+(iterationCount-1)*s, s);	// make copy first in case of in-place decryption
+		m_cipher->AdvancedProcessBlocks(input, input+s, output+s, (iterationCount-1)*s, BlockTransformation::BT_ReverseDirection);
+		m_cipher->ProcessAndXorBlock(m_register, input, output);
+		memcpy(m_register, m_temp, s);
+	}
+}
+
+void CFB_ModePolicy::TransformRegister()
+{
+	assert(m_cipher->IsForwardTransformation());	// CFB mode needs the "encrypt" direction of the underlying block cipher, even to decrypt
+	m_cipher->ProcessBlock(m_register, m_temp);
+	unsigned int updateSize = BlockSize()-m_feedbackSize;
+	memmove_s(m_register, m_register.size(), m_register+m_feedbackSize, updateSize);
+	memcpy_s(m_register+updateSize, m_register.size()-updateSize, m_temp, m_feedbackSize);
+}
+
+void CFB_ModePolicy::CipherResynchronize(const byte *iv, size_t length)
+{
+	assert(length == BlockSize());
+	CopyOrZero(m_register, iv, length);
+	TransformRegister();
+}
+
+void CFB_ModePolicy::SetFeedbackSize(unsigned int feedbackSize)
+{
+	if (feedbackSize > BlockSize())
+		throw InvalidArgument("CFB_Mode: invalid feedback size");
+	m_feedbackSize = feedbackSize ? feedbackSize : BlockSize();
+}
+
+void CFB_ModePolicy::ResizeBuffers()
+{
+	CipherModeBase::ResizeBuffers();
+	m_temp.New(BlockSize());
+}
+
+void OFB_ModePolicy::WriteKeystream(byte *keystreamBuffer, size_t iterationCount)
+{
+	assert(m_cipher->IsForwardTransformation());	// OFB mode needs the "encrypt" direction of the underlying block cipher, even to decrypt
+	unsigned int s = BlockSize();
+	m_cipher->ProcessBlock(m_register, keystreamBuffer);
+	if (iterationCount > 1)
+		m_cipher->AdvancedProcessBlocks(keystreamBuffer, NULL, keystreamBuffer+s, s*(iterationCount-1), 0);
+	memcpy(m_register, keystreamBuffer+s*(iterationCount-1), s);
+}
+
+void OFB_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length)
+{
+	assert(length == BlockSize());
+	CopyOrZero(m_register, iv, length);
+}
+
+void CTR_ModePolicy::SeekToIteration(lword iterationCount)
+{
+	int carry=0;
+	for (int i=BlockSize()-1; i>=0; i--)
+	{
+		unsigned int sum = m_register[i] + byte(iterationCount) + carry;
+		m_counterArray[i] = (byte) sum;
+		carry = sum >> 8;
+		iterationCount >>= 8;
+	}
+}
+
+void CTR_ModePolicy::IncrementCounterBy256()
+{
+	IncrementCounterByOne(m_counterArray, BlockSize()-1);
+}
+
+void CTR_ModePolicy::OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)
+{
+	assert(m_cipher->IsForwardTransformation());	// CTR mode needs the "encrypt" direction of the underlying block cipher, even to decrypt
+	unsigned int s = BlockSize();
+	unsigned int inputIncrement = input ? s : 0;
+
+	while (iterationCount)
+	{
+		byte lsb = m_counterArray[s-1];
+		size_t blocks = UnsignedMin(iterationCount, 256U-lsb);
+		m_cipher->AdvancedProcessBlocks(m_counterArray, input, output, blocks*s, BlockTransformation::BT_InBlockIsCounter|BlockTransformation::BT_AllowParallel);
+		if ((m_counterArray[s-1] = lsb + (byte)blocks) == 0)
+			IncrementCounterBy256();
+
+		output += blocks*s;
+		input += blocks*inputIncrement;
+		iterationCount -= blocks;
+	}
+}
+
+void CTR_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length)
+{
+	assert(length == BlockSize());
+	CopyOrZero(m_register, iv, length);
+	m_counterArray = m_register;
+}
+
+void BlockOrientedCipherModeBase::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
+{
+	m_cipher->SetKey(key, length, params);
+	ResizeBuffers();
+	if (IsResynchronizable())
+	{
+		size_t ivLength;
+		const byte *iv = GetIVAndThrowIfInvalid(params, ivLength);
+		Resynchronize(iv, (int)ivLength);
+	}
+}
+
+void ECB_OneWay::ProcessData(byte *outString, const byte *inString, size_t length)
+{
+	assert(length%BlockSize()==0);
+	m_cipher->AdvancedProcessBlocks(inString, NULL, outString, length, BlockTransformation::BT_AllowParallel);
+}
+
+void CBC_Encryption::ProcessData(byte *outString, const byte *inString, size_t length)
+{
+	if (!length)
+		return;
+	assert(length%BlockSize()==0);
+
+	unsigned int blockSize = BlockSize();
+	m_cipher->AdvancedProcessBlocks(inString, m_register, outString, blockSize, BlockTransformation::BT_XorInput);
+	if (length > blockSize)
+		m_cipher->AdvancedProcessBlocks(inString+blockSize, outString, outString+blockSize, length-blockSize, BlockTransformation::BT_XorInput);
+	memcpy(m_register, outString + length - blockSize, blockSize);
+}
+
+void CBC_CTS_Encryption::ProcessLastBlock(byte *outString, const byte *inString, size_t length)
+{
+	if (length <= BlockSize())
+	{
+		if (!m_stolenIV)
+			throw InvalidArgument("CBC_Encryption: message is too short for ciphertext stealing");
+
+		// steal from IV
+		memcpy(outString, m_register, length);
+		outString = m_stolenIV;
+	}
+	else
+	{
+		// steal from next to last block
+		xorbuf(m_register, inString, BlockSize());
+		m_cipher->ProcessBlock(m_register);
+		inString += BlockSize();
+		length -= BlockSize();
+		memcpy(outString+BlockSize(), m_register, length);
+	}
+
+	// output last full ciphertext block
+	xorbuf(m_register, inString, length);
+	m_cipher->ProcessBlock(m_register);
+	memcpy(outString, m_register, BlockSize());
+}
+
+void CBC_Decryption::ProcessData(byte *outString, const byte *inString, size_t length)
+{
+	if (!length)
+		return;
+	assert(length%BlockSize()==0);
+
+	unsigned int blockSize = BlockSize();
+	memcpy(m_temp, inString+length-blockSize, blockSize);	// save copy now in case of in-place decryption
+	if (length > blockSize)
+		m_cipher->AdvancedProcessBlocks(inString+blockSize, inString, outString+blockSize, length-blockSize, BlockTransformation::BT_ReverseDirection|BlockTransformation::BT_AllowParallel);
+	m_cipher->ProcessAndXorBlock(inString, m_register, outString);
+	m_register.swap(m_temp);
+}
+
+void CBC_CTS_Decryption::ProcessLastBlock(byte *outString, const byte *inString, size_t length)
+{
+	const byte *pn, *pn1;
+	bool stealIV = length <= BlockSize();
+
+	if (stealIV)
+	{
+		pn = inString;
+		pn1 = m_register;
+	}
+	else
+	{
+		pn = inString + BlockSize();
+		pn1 = inString;
+		length -= BlockSize();
+	}
+
+	// decrypt last partial plaintext block
+	memcpy(m_temp, pn1, BlockSize());
+	m_cipher->ProcessBlock(m_temp);
+	xorbuf(m_temp, pn, length);
+
+	if (stealIV)
+		memcpy(outString, m_temp, length);
+	else
+	{
+		memcpy(outString+BlockSize(), m_temp, length);
+		// decrypt next to last plaintext block
+		memcpy(m_temp, pn, length);
+		m_cipher->ProcessBlock(m_temp);
+		xorbuf(outString, m_temp, m_register, BlockSize());
+	}
+}
+
+NAMESPACE_END
+
+#endif