chacha.h
Go to the documentation of this file.
// chacha.h - written and placed in the public domain by Jeffrey Walton.
// Copyright assigned to the Crypto++ project.
// Based on Wei Dai's Salsa20 and Bernstein's reference ChaCha
// family implementation at http://cr.yp.to/chacha.html.
//! \file chacha.h
//! \brief Classes for ChaCha8, ChaCha12 and ChaCha20 stream ciphers
//! \since Crypto++ 5.6.4
#ifndef CRYPTOPP_CHACHA_H
#define CRYPTOPP_CHACHA_H
#include "strciphr.h"
#include "secblock.h"
NAMESPACE_BEGIN(CryptoPP)
//! \class ChaCha_Info
//! \brief ChaCha stream cipher information
//! \since Crypto++ 5.6.4
template <unsigned int R>
struct ChaCha_Info : public VariableKeyLength<32, 16, 32, 16, SimpleKeyingInterface::UNIQUE_IV, 8>, public FixedRounds<R>
{
CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {
return (R==8?"ChaCha8":(R==12?"ChaCha12":(R==20?"ChaCha20":"ChaCha")));
}
};
//! \class ChaCha_Policy
//! \brief ChaCha stream cipher implementation
//! \since Crypto++ 5.6.4
template <unsigned int R>
class CRYPTOPP_NO_VTABLE ChaCha_Policy : public AdditiveCipherConcretePolicy<word32, 16>
{
protected:
CRYPTOPP_CONSTANT(ROUNDS=FixedRounds<R>::ROUNDS)
void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length);
void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount);
void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length);
bool CipherIsRandomAccess() const {return false;} // TODO
void SeekToIteration(lword iterationCount);
unsigned int GetAlignment() const;
unsigned int GetOptimalBlockSize() const;
FixedSizeAlignedSecBlock<word32, 16> m_state;
};
//! \class ChaCha8
//! \brief ChaCha8 stream cipher
//! \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
//! \since Crypto++ 5.6.4
struct ChaCha8 : public ChaCha_Info<8>, public SymmetricCipherDocumentation
{
typedef SymmetricCipherFinal<ConcretePolicyHolder<ChaCha_Policy<8>, AdditiveCipherTemplate<> >, ChaCha_Info<8> > Encryption;
typedef Encryption Decryption;
};
//! \class ChaCha12
//! \brief ChaCha12 stream cipher
//! \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
//! \since Crypto++ 5.6.4
struct ChaCha12 : public ChaCha_Info<12>, public SymmetricCipherDocumentation
{
typedef SymmetricCipherFinal<ConcretePolicyHolder<ChaCha_Policy<12>, AdditiveCipherTemplate<> >, ChaCha_Info<12> > Encryption;
typedef Encryption Decryption;
};
//! \class ChaCha20
//! \brief ChaCha20 stream cipher
//! \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
//! \since Crypto++ 5.6.4
struct ChaCha20 : public ChaCha_Info<20>, public SymmetricCipherDocumentation
{
typedef SymmetricCipherFinal<ConcretePolicyHolder<ChaCha_Policy<20>, AdditiveCipherTemplate<> >, ChaCha_Info<20> > Encryption;
typedef Encryption Decryption;
};
NAMESPACE_END
#endif // CRYPTOPP_CHACHA_H
AdditiveCipherAbstractPolicy::CipherIsRandomAccess
virtual bool CipherIsRandomAccess() const =0
Flag indicating random access.
ChaCha12
ChaCha12 stream cipher.
Definition: chacha.h:63
FixedSizeAlignedSecBlock< word32, 16 >
ChaCha20
ChaCha20 stream cipher.
Definition: chacha.h:73
AdditiveCipherAbstractPolicy::CipherResynchronize
virtual void CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length)
Resynchronize the cipher.
Definition: strciphr.h:166
SymmetricCipherDocumentation
Provides Encryption and Decryption typedefs used by derived classes to implement a symmetric cipher.
Definition: seckey.h:439
SymmetricCipherFinal
SymmetricCipher implementation.
Definition: strciphr.h:582
AdditiveCipherConcretePolicy
Base class for additive stream ciphers.
Definition: strciphr.h:188
ChaCha_Policy
ChaCha stream cipher implementation.
Definition: chacha.h:33
AdditiveCipherAbstractPolicy::CipherSetKey
virtual void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length)=0
Key the cipher.
secblock.h
Classes and functions for secure memory allocations.
ChaCha8
ChaCha8 stream cipher.
Definition: chacha.h:53
AdditiveCipherTemplate
Base class for additive stream ciphers with SymmetricCipher interface.
Definition: strciphr.h:269
KeystreamOperation
KeystreamOperation
Keystream operation flags.
Definition: strciphr.h:92
ChaCha_Info
ChaCha stream cipher information.
Definition: chacha.h:22
CryptoPP
Crypto++ library namespace.
AdditiveCipherAbstractPolicy::SeekToIteration
virtual void SeekToIteration(lword iterationCount)
Seeks to a random position in the stream.
Definition: strciphr.h:177
AdditiveCipherConcretePolicy::GetAlignment
unsigned int GetAlignment() const
Provides data alignment requirements.
Definition: strciphr.h:198
AdditiveCipherConcretePolicy::OperateKeystream
virtual void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)=0
Operates the keystream.
AdditiveCipherAbstractPolicy::GetOptimalBlockSize
virtual unsigned int GetOptimalBlockSize() const
Provides number of ideal bytes to process.
Definition: strciphr.h:127
NameValuePairs
Interface for retrieving values given their names.
Definition: cryptlib.h:277
FixedRounds
Inherited by algorithms with fixed number of rounds.
Definition: seckey.h:47
strciphr.h
Classes for implementing stream ciphers.
VariableKeyLength
Inherited by keyed algorithms with variable key length.
Definition: seckey.h:177