modes.cpp
// modes.cpp - originally written and placed in the public domain by Wei Dai
#include "pch.h"
#ifndef CRYPTOPP_IMPORTS
#include "modes.h"
#include "strciphr.h"
#include "misc.h"
#if defined(CRYPTOPP_DEBUG)
#include "des.h"
#endif
NAMESPACE_BEGIN(CryptoPP)
#if defined(CRYPTOPP_DEBUG) && !defined(CRYPTOPP_DOXYGEN_PROCESSING)
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 CipherModeBase::ResizeBuffers()
{
m_register.New(m_cipher->BlockSize());
}
void CFB_ModePolicy::Iterate(byte *output, const byte *input, CipherDir dir, size_t iterationCount)
{
CRYPTOPP_ASSERT(input); CRYPTOPP_ASSERT(output);
CRYPTOPP_ASSERT(m_cipher->IsForwardTransformation());
CRYPTOPP_ASSERT(m_register.size() == BlockSize());
CRYPTOPP_ASSERT(m_temp.size() == BlockSize());
CRYPTOPP_ASSERT(iterationCount > 0);
const unsigned int s = BlockSize();
if (dir == ENCRYPTION)
{
m_cipher->ProcessAndXorBlock(m_register, input, output);
if (iterationCount > 1)
m_cipher->AdvancedProcessBlocks(output, PtrAdd(input,s), PtrAdd(output,s), (iterationCount-1)*s, 0);
std::memcpy(m_register, PtrAdd(output,(iterationCount-1)*s), s);
}
else
{
// make copy first in case of in-place decryption
std::memcpy(m_temp, PtrAdd(input,(iterationCount-1)*s), s);
if (iterationCount > 1)
m_cipher->AdvancedProcessBlocks(input, PtrAdd(input,s), PtrAdd(output,s), (iterationCount-1)*s, BlockTransformation::BT_ReverseDirection);
m_cipher->ProcessAndXorBlock(m_register, input, output);
std::memcpy(m_register, m_temp, s);
}
}
void CFB_ModePolicy::TransformRegister()
{
CRYPTOPP_ASSERT(m_cipher->IsForwardTransformation());
CRYPTOPP_ASSERT(m_register.size() == BlockSize());
CRYPTOPP_ASSERT(m_temp.size() == BlockSize());
const ptrdiff_t updateSize = BlockSize()-m_feedbackSize;
m_cipher->ProcessBlock(m_register, m_temp);
memmove_s(m_register, m_register.size(), PtrAdd(m_register.begin(),m_feedbackSize), updateSize);
memcpy_s(PtrAdd(m_register.begin(),updateSize), m_register.size()-updateSize, m_temp, m_feedbackSize);
}
void CFB_ModePolicy::CipherResynchronize(const byte *iv, size_t length)
{
CRYPTOPP_ASSERT(length == BlockSize());
CRYPTOPP_ASSERT(m_register.size() == BlockSize());
CopyOrZero(m_register, m_register.size(), iv, length);
TransformRegister();
}
void CFB_ModePolicy::SetFeedbackSize(unsigned int feedbackSize)
{
CRYPTOPP_ASSERT(feedbackSize <= BlockSize());
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());
}
byte* CFB_ModePolicy::GetRegisterBegin()
{
CRYPTOPP_ASSERT(!m_register.empty());
CRYPTOPP_ASSERT(BlockSize() >= m_feedbackSize);
return PtrAdd(m_register.begin(), BlockSize() - m_feedbackSize);
}
void OFB_ModePolicy::WriteKeystream(byte *keystreamBuffer, size_t iterationCount)
{
CRYPTOPP_ASSERT(m_cipher->IsForwardTransformation());
CRYPTOPP_ASSERT(m_register.size() == BlockSize());
CRYPTOPP_ASSERT(iterationCount > 0);
const unsigned int s = BlockSize();
m_cipher->ProcessBlock(m_register, keystreamBuffer);
if (iterationCount > 1)
m_cipher->AdvancedProcessBlocks(keystreamBuffer, NULLPTR, PtrAdd(keystreamBuffer, s), s*(iterationCount-1), 0);
std::memcpy(m_register, PtrAdd(keystreamBuffer, (iterationCount-1)*s), s);
}
void OFB_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length)
{
CRYPTOPP_UNUSED(keystreamBuffer), CRYPTOPP_UNUSED(length);
CRYPTOPP_ASSERT(m_register.size() == BlockSize());
CRYPTOPP_ASSERT(length == BlockSize());
CopyOrZero(m_register, m_register.size(), 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 & 0xff);
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)
{
CRYPTOPP_ASSERT(output);
// CRYPTOPP_ASSERT(input); // input is sometimes NULL
CRYPTOPP_ASSERT(m_cipher->IsForwardTransformation());
CRYPTOPP_ASSERT(m_counterArray.size() == BlockSize());
CRYPTOPP_UNUSED(operation);
const size_t s = BlockSize();
while (iterationCount)
{
const byte lsb = m_counterArray[s-1];
const size_t blocks = UnsignedMin(iterationCount, 256u-lsb);
const size_t outIncrement = output ? blocks*s : 0;
const size_t inIncrement = input ? blocks*s : 0;
m_cipher->AdvancedProcessBlocks(m_counterArray, input, output, blocks*s, BlockTransformation::BT_InBlockIsCounter|BlockTransformation::BT_AllowParallel);
if ((m_counterArray[s-1] = static_cast<byte>(lsb + blocks)) == 0)
IncrementCounterBy256();
output = PtrAdd(output, outIncrement);
input = PtrAdd(input, inIncrement);
iterationCount -= blocks;
}
}
void CTR_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length)
{
CRYPTOPP_UNUSED(keystreamBuffer), CRYPTOPP_UNUSED(length);
CRYPTOPP_ASSERT(m_register.size() == BlockSize());
CRYPTOPP_ASSERT(length == BlockSize());
CopyOrZero(m_register, m_register.size(), iv, length);
m_counterArray.Assign(m_register.begin(), m_register.size());
}
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 BlockOrientedCipherModeBase::ResizeBuffers()
{
CipherModeBase::ResizeBuffers();
m_buffer.New(BlockSize());
}
void ECB_OneWay::ProcessData(byte *outString, const byte *inString, size_t length)
{
CRYPTOPP_ASSERT(length%BlockSize()==0);
m_cipher->AdvancedProcessBlocks(inString, NULLPTR, outString, length, BlockTransformation::BT_AllowParallel);
}
void CBC_Encryption::ProcessData(byte *outString, const byte *inString, size_t length)
{
CRYPTOPP_ASSERT(length%BlockSize()==0);
CRYPTOPP_ASSERT(m_register.size() == BlockSize());
if (!length) return;
const unsigned int blockSize = BlockSize();
m_cipher->AdvancedProcessBlocks(inString, m_register, outString, blockSize, BlockTransformation::BT_XorInput);
if (length > blockSize)
m_cipher->AdvancedProcessBlocks(PtrAdd(inString,blockSize), outString, PtrAdd(outString,blockSize), length-blockSize, BlockTransformation::BT_XorInput);
std::memcpy(m_register, PtrAdd(outString, length - blockSize), blockSize);
}
size_t CBC_CTS_Encryption::ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
{
CRYPTOPP_UNUSED(outLength);
const size_t used = inLength;
const unsigned int blockSize = BlockSize();
if (inLength <= blockSize)
{
if (!m_stolenIV)
throw InvalidArgument("CBC_Encryption: message is too short for ciphertext stealing");
// steal from IV
std::memcpy(outString, m_register, inLength);
outString = m_stolenIV;
}
else
{
// steal from next to last block
xorbuf(m_register, inString, blockSize);
m_cipher->ProcessBlock(m_register);
inString = PtrAdd(inString, blockSize);
inLength -= blockSize;
std::memcpy(PtrAdd(outString, blockSize), m_register, inLength);
}
// output last full ciphertext block
xorbuf(m_register, inString, inLength);
m_cipher->ProcessBlock(m_register);
std::memcpy(outString, m_register, blockSize);
return used;
}
void CBC_Decryption::ResizeBuffers()
{
BlockOrientedCipherModeBase::ResizeBuffers();
m_temp.New(BlockSize());
}
void CBC_Decryption::ProcessData(byte *outString, const byte *inString, size_t length)
{
CRYPTOPP_ASSERT(length%BlockSize()==0);
if (!length) {return;}
// save copy now in case of in-place decryption
const unsigned int blockSize = BlockSize();
std::memcpy(m_temp, PtrAdd(inString, length-blockSize), blockSize);
if (length > blockSize)
m_cipher->AdvancedProcessBlocks(PtrAdd(inString,blockSize), inString, PtrAdd(outString,blockSize), length-blockSize, BlockTransformation::BT_ReverseDirection|BlockTransformation::BT_AllowParallel);
m_cipher->ProcessAndXorBlock(inString, m_register, outString);
m_register.swap(m_temp);
}
size_t CBC_CTS_Decryption::ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
{
CRYPTOPP_UNUSED(outLength);
const byte *pn1, *pn2;
const size_t used = inLength;
const bool stealIV = inLength <= BlockSize();
const unsigned int blockSize = BlockSize();
if (stealIV)
{
pn1 = inString;
pn2 = m_register;
}
else
{
pn1 = PtrAdd(inString, blockSize);
pn2 = inString;
inLength -= blockSize;
}
// decrypt last partial plaintext block
std::memcpy(m_temp, pn2, blockSize);
m_cipher->ProcessBlock(m_temp);
xorbuf(m_temp, pn1, inLength);
if (stealIV)
{
std::memcpy(outString, m_temp, inLength);
}
else
{
std::memcpy(PtrAdd(outString, blockSize), m_temp, inLength);
// decrypt next to last plaintext block
std::memcpy(m_temp, pn1, inLength);
m_cipher->ProcessBlock(m_temp);
xorbuf(outString, m_temp, m_register, blockSize);
}
return used;
}
NAMESPACE_END
#endif
BlockOrientedCipherModeBase::UncheckedSetKey
void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
Sets the key for this object without performing parameter validation.
BlockOrientedCipherModeBase::Resynchronize
void Resynchronize(const byte *iv, int length=-1)
Resynchronize with an IV.
Definition modes.h:260
BlockTransformation::BT_InBlockIsCounter
@ BT_InBlockIsCounter
inBlock is a counter
Definition cryptlib.h:922
BlockTransformation::BT_ReverseDirection
@ BT_ReverseDirection
perform the transformation in reverse
Definition cryptlib.h:928
BlockTransformation::BT_XorInput
@ BT_XorInput
Xor inputs before transformation.
Definition cryptlib.h:926
BlockTransformation::BT_AllowParallel
@ BT_AllowParallel
Allow parallel transformations.
Definition cryptlib.h:930
BlockTransformation::BlockSize
virtual unsigned int BlockSize() const =0
Provides the block size of the cipher.
CBC_CTS_Decryption::ProcessLastBlock
size_t ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
Encrypt or decrypt the last block of data.
CBC_CTS_Encryption::ProcessLastBlock
size_t ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
Encrypt or decrypt the last block of data.
CBC_Decryption::ProcessData
void ProcessData(byte *outString, const byte *inString, size_t length)
Encrypt or decrypt an array of bytes.
CBC_Encryption::ProcessData
void ProcessData(byte *outString, const byte *inString, size_t length)
Encrypt or decrypt an array of bytes.
CipherModeFinalTemplate_CipherHolder
Block cipher mode of operation aggregate.
Definition modes.h:347
ECB_OneWay::ProcessData
void ProcessData(byte *outString, const byte *inString, size_t length)
Encrypt or decrypt an array of bytes.
InvalidArgument
An invalid argument was detected.
Definition cryptlib.h:208
NameValuePairs
Interface for retrieving values given their names.
Definition cryptlib.h:327
SecBlock::New
void New(size_type newSize)
Change size without preserving contents.
Definition secblock.h:1126
SecBlock::Assign
void Assign(const T *ptr, size_type len)
Set contents and size from an array.
Definition secblock.h:898
SecBlock::size
size_type size() const
Provides the count of elements in the SecBlock.
Definition secblock.h:867
SimpleKeyingInterface::IsResynchronizable
bool IsResynchronizable() const
Determines if the object can be resynchronized.
Definition cryptlib.h:745
byte
unsigned char byte
8-bit unsigned datatype
Definition config_int.h:66
lword
word64 lword
Large word type.
Definition config_int.h:168
CipherDir
CipherDir
Specifies a direction for a cipher to operate.
Definition cryptlib.h:128
ENCRYPTION
@ ENCRYPTION
the cipher is performing encryption
Definition cryptlib.h:130
des.h
Classes for DES, 2-key Triple-DES, 3-key Triple-DES and DESX.
misc.h
Utility functions for the Crypto++ library.
IncrementCounterByOne
void IncrementCounterByOne(byte *inout, unsigned int size)
Performs an addition with carry on a block of bytes.
Definition misc.h:1508
memcpy_s
void memcpy_s(void *dest, size_t sizeInBytes, const void *src, size_t count)
Bounds checking replacement for memcpy()
Definition misc.h:527
PtrAdd
PTR PtrAdd(PTR pointer, OFF offset)
Create a pointer with an offset.
Definition misc.h:388
UnsignedMin
const T1 UnsignedMin(const T1 &a, const T2 &b)
Safe comparison of values that could be negative and incorrectly promoted.
Definition misc.h:695
memmove_s
void memmove_s(void *dest, size_t sizeInBytes, const void *src, size_t count)
Bounds checking replacement for memmove()
Definition misc.h:573
xorbuf
CRYPTOPP_DLL void xorbuf(byte *buf, const byte *mask, size_t count)
Performs an XOR of a buffer with a mask.
modes.h
Classes for block cipher modes of operation.
CopyOrZero
void CopyOrZero(void *dest, size_t dsize, const void *src, size_t ssize)
Initialize a block of memory.
Definition modes.h:196
CryptoPP
Crypto++ library namespace.
Name::BlockSize
const char * BlockSize()
int, in bytes
Definition argnames.h:27
pch.h
Precompiled header file.
strciphr.h
Classes for implementing stream ciphers.
KeystreamOperation
KeystreamOperation
Keystream operation flags.
Definition strciphr.h:88
CRYPTOPP_ASSERT
#define CRYPTOPP_ASSERT(exp)
Debugging and diagnostic assertion.
Definition trap.h:68