ChaCha stream cipher implementation. More...

#include <chacha.h>

Inheritance diagram for ChaCha_Policy< R >:

Collaboration diagram for ChaCha_Policy< R >:

Protected Member Functions
void	CipherSetKey (const NameValuePairs &params, const byte *key, size_t length)
	Key the cipher. More...

void	OperateKeystream (KeystreamOperation operation, byte output, const byte input, size_t iterationCount)
	Operates the keystream. More...

void	CipherResynchronize (byte keystreamBuffer, const byte IV, size_t length)
	Resynchronize the cipher. More...

bool	CipherIsRandomAccess () const
	Flag indicating random access. More...

void	SeekToIteration (lword iterationCount)
	Seeks to a random position in the stream. More...

unsigned int	GetAlignment () const
	Provides data alignment requirements. More...

unsigned int	GetOptimalBlockSize () const
	Provides number of ideal bytes to process. More...

Protected Attributes
FixedSizeAlignedSecBlock< word32, 16 >	m_state

Additional Inherited Members
Public Types inherited from AdditiveCipherConcretePolicy< word32, 16 >
typedef word32	WordType

Public Member Functions inherited from AdditiveCipherConcretePolicy< word32, 16 >
unsigned int	GetAlignment () const
	Provides data alignment requirements. More...

unsigned int	GetBytesPerIteration () const
	Provides number of bytes operated upon during an iteration. More...

unsigned int	GetIterationsToBuffer () const
	Provides buffer size based on iterations. More...

bool	CanOperateKeystream () const
	Flag indicating. More...

Public Member Functions inherited from AdditiveCipherAbstractPolicy
virtual	~AdditiveCipherAbstractPolicy ()

virtual void	WriteKeystream (byte *keystream, size_t iterationCount)
	Generate the keystream. More...

Detailed Description

template<unsigned int R>
class ChaCha_Policy< R >

ChaCha stream cipher implementation.

Since: Crypto++ 5.6.4

Definition at line 37 of file chacha.h.

Member Function Documentation

template<unsigned int R>

bool ChaCha_Policy< R >::CipherIsRandomAccess ( ) const

inlineprotectedvirtual

Flag indicating random access.

Returns: true if the cipher is seekable, false otherwise

See also: SeekToIteration()

Implements AdditiveCipherAbstractPolicy.

Definition at line 45 of file chacha.h.

Here is the call graph for this function:

template<unsigned int R>

void ChaCha_Policy< R >::CipherResynchronize	(	byte *	keystreamBuffer,
		const byte *	iv,
		size_t	length
	)

protectedvirtual

Resynchronize the cipher.

Parameters

keystreamBuffer	the keystream buffer
iv	a byte array used to resynchronize the cipher
length	the size of the IV array

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 50 of file chacha.cpp.

template<unsigned int R>

void ChaCha_Policy< R >::CipherSetKey	(	const NameValuePairs &	params,
		const byte *	key,
		size_t	length
	)

protectedvirtual

Key the cipher.

Parameters

params	set of NameValuePairs use to initialize this object
key	a byte array used to key the cipher
length	the size of the key array

Implements AdditiveCipherAbstractPolicy.

Definition at line 31 of file chacha.cpp.

template<unsigned int R>

unsigned int ChaCha_Policy< R >::GetAlignment ( ) const

protectedvirtual

Provides data alignment requirements.

Returns: data alignment requirements, in bytes

Internally, the default implementation returns 1. If the stream cipher is implemented using an SSE2 ASM or intrinsics, then the value returned is usually 16.

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 74 of file chacha.cpp.

template<unsigned int R>

unsigned int ChaCha_Policy< R >::GetOptimalBlockSize ( ) const

protectedvirtual

Provides number of ideal bytes to process.

Returns: the ideal number of bytes to process

Internally, the default implementation returns GetBytesPerIteration()

See also: GetBytesPerIteration()

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 85 of file chacha.cpp.

template<unsigned int R>

void ChaCha_Policy< R >::OperateKeystream	(	KeystreamOperation	operation,
		byte *	output,
		const byte *	input,
		size_t	iterationCount
	)

protectedvirtual

Operates the keystream.

Parameters

operation	the operation with additional flags
output	the output buffer
input	the input buffer
iterationCount	the number of iterations to perform on the input

OperateKeystream() will attempt to operate upon GetOptimalBlockSize() buffer, which will be derived from GetBytesPerIteration().