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// modes.cpp - written and placed in the public domain by Wei Dai
#include "pch.h"
#include "modes.h"
#include "des.h"
#include "strciphr.cpp"
NAMESPACE_BEGIN(CryptoPP)
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;
}
// explicit instantiations for Darwin gcc-932.1
template class CFB_CipherTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, SymmetricCipher> >;
template class CFB_EncryptionTemplate<>;
template class CFB_DecryptionTemplate<>;
template class AdditiveCipherTemplate<>;
template class CFB_CipherTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;
template class CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;
template class CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;
template class AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, OFB_ModePolicy> >;
template class AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, CTR_ModePolicy> >;
void CipherModeBase::SetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms)
{
UncheckedSetKey(params, key, length); // the underlying cipher will check the key length
}
void CipherModeBase::GetNextIV(byte *IV)
{
if (!IsForwardTransformation())
throw NotImplemented("CipherModeBase: GetNextIV() must be called on an encryption object");
m_cipher->ProcessBlock(m_register);
memcpy(IV, m_register, BlockSize());
}
void CipherModeBase::SetIV(const byte *iv)
{
if (iv)
Resynchronize(iv);
else if (IsResynchronizable())
{
if (!CanUseStructuredIVs())
throw InvalidArgument("CipherModeBase: this cipher mode cannot use a null IV");
// use all zeros as default IV
SecByteBlock iv(BlockSize());
memset(iv, 0, iv.size());
Resynchronize(iv);
}
}
void CTR_ModePolicy::SeekToIteration(dword iterationCount)
{
int carry=0;
for (int i=BlockSize()-1; i>=0 && (iterationCount || carry); i--)
{
unsigned int sum = m_counterArray[i] + byte(iterationCount) + carry;
m_counterArray[i] = (byte) sum;
carry = sum >> 8;
iterationCount >>= 8;
}
}
void CTR_ModePolicy::OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, unsigned int iterationCount)
{
unsigned int maxBlocks = m_cipher->OptimalNumberOfParallelBlocks();
unsigned int sizeIncrement = maxBlocks * m_cipher->BlockSize();
while (iterationCount >= maxBlocks)
{
ProcessMultipleBlocks(output, input, maxBlocks);
output += sizeIncrement;
input += sizeIncrement;
iterationCount -= maxBlocks;
}
if (iterationCount > 0)
ProcessMultipleBlocks(output, input, iterationCount);
}
void CTR_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv)
{
unsigned int s = BlockSize();
memcpy(m_register, iv, s);
m_counterArray.New(s * m_cipher->OptimalNumberOfParallelBlocks());
memcpy(m_counterArray, iv, s);
}
void BlockOrientedCipherModeBase::UncheckedSetKey(const NameValuePairs ¶ms, const byte *key, unsigned int length)
{
m_cipher->SetKey(key, length, params);
ResizeBuffers();
const byte *iv = params.GetValueWithDefault(Name::IV(), (const byte *)NULL);
SetIV(iv);
}
void BlockOrientedCipherModeBase::ProcessData(byte *outString, const byte *inString, unsigned int length)
{
unsigned int s = BlockSize();
assert(length % s == 0);
unsigned int alignment = m_cipher->BlockAlignment();
bool requireAlignedInput = RequireAlignedInput();
if (IsAlignedOn(outString, alignment))
{
if (!requireAlignedInput || IsAlignedOn(inString, alignment))
ProcessBlocks(outString, inString, length / s);
else
{
memcpy(outString, inString, length);
ProcessBlocks(outString, outString, length / s);
}
}
else
{
while (length)
{
if (!requireAlignedInput || IsAlignedOn(inString, alignment))
ProcessBlocks(m_buffer, inString, 1);
else
{
memcpy(m_buffer, inString, s);
ProcessBlocks(m_buffer, m_buffer, 1);
}
memcpy(outString, m_buffer, s);
length -= s;
}
}
}
void CBC_Encryption::ProcessBlocks(byte *outString, const byte *inString, unsigned int numberOfBlocks)
{
unsigned int blockSize = BlockSize();
while (numberOfBlocks--)
{
xorbuf(m_register, inString, blockSize);
m_cipher->ProcessBlock(m_register);
memcpy(outString, m_register, blockSize);
inString += blockSize;
outString += blockSize;
}
}
void CBC_CTS_Encryption::ProcessLastBlock(byte *outString, const byte *inString, unsigned int 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::ProcessBlocks(byte *outString, const byte *inString, unsigned int numberOfBlocks)
{
unsigned int blockSize = BlockSize();
while (numberOfBlocks--)
{
memcpy(m_temp, inString, blockSize);
m_cipher->ProcessBlock(m_temp, outString);
xorbuf(outString, m_register, blockSize);
m_register.swap(m_temp);
inString += blockSize;
outString += blockSize;
}
}
void CBC_CTS_Decryption::ProcessLastBlock(byte *outString, const byte *inString, unsigned int 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
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