Base class for additive stream ciphers. More...

#include <strciphr.h>

Inheritance diagram for AdditiveCipherConcretePolicy< WT, W, X, BASE >:

Public Types
typedef WT	WordType
	Word type for the cipher.

Public Member Functions
	CRYPTOPP_CONSTANT (BYTES_PER_ITERATION=sizeof(WordType) *W)
	Number of bytes for an iteration.

unsigned int	GetAlignment () const
	Provides data alignment requirements.

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

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

bool	CanOperateKeystream () const
	Flag indicating.

virtual void	OperateKeystream (KeystreamOperation operation, byte output, const byte input, size_t iterationCount)=0
	Operates the keystream.

Public Member Functions inherited from AdditiveCipherAbstractPolicy
virtual unsigned int	GetOptimalBlockSize () const
	Provides number of ideal bytes to process.

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

virtual void	CipherSetKey (const NameValuePairs &params, const byte *key, size_t length)=0
	Key the cipher.

virtual void	CipherResynchronize (byte keystreamBuffer, const byte iv, size_t length)
	Resynchronize the cipher.

virtual bool	CipherIsRandomAccess () const =0
	Flag indicating random access.

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

virtual std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm.

Detailed Description

template<typename WT, unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>
struct AdditiveCipherConcretePolicy< WT, W, X, BASE >

Base class for additive stream ciphers.

Template Parameters

WT	word type
W	count of words
X	bytes per iteration count
BASE	AdditiveCipherAbstractPolicy derived base class

Definition at line 201 of file strciphr.h.

Member Typedef Documentation

◆ WordType

template<typename WT , unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>

typedef WT AdditiveCipherConcretePolicy< WT, W, X, BASE >::WordType

Word type for the cipher.

Definition at line 204 of file strciphr.h.

Constructor & Destructor Documentation

◆ ~AdditiveCipherConcretePolicy()

template<typename WT , unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>

virtual AdditiveCipherConcretePolicy< WT, W, X, BASE >::~AdditiveCipherConcretePolicy ( )

inlinevirtual

Definition at line 213 of file strciphr.h.

Member Function Documentation

◆ CanOperateKeystream()

template<typename WT , unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>

bool AdditiveCipherConcretePolicy< WT, W, X, BASE >::CanOperateKeystream ( ) const

inlinevirtual

Flag indicating.

Returns: true if the stream can be generated independent of the transformation input, false otherwise

See also: CanOperateKeystream(), OperateKeystream(), WriteKeystream()

Reimplemented from AdditiveCipherAbstractPolicy.

Reimplemented in HC128Policy, HC256Policy, RabbitPolicy, and RabbitWithIVPolicy.

Definition at line 235 of file strciphr.h.

◆ CRYPTOPP_CONSTANT()

template<typename WT , unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>

AdditiveCipherConcretePolicy< WT, W, X, BASE >::CRYPTOPP_CONSTANT ( BYTES_PER_ITERATION = sizeof(WordType) *W )

Number of bytes for an iteration.

BYTES_PER_ITERATION is the product sizeof(WordType) * W. For example, ChaCha uses 16 each word32, and the value of BYTES_PER_ITERATION is 64. Each invocation of the ChaCha block function produces 64 bytes of keystream.

◆ GetAlignment()

template<typename WT , unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>

unsigned int AdditiveCipherConcretePolicy< WT, W, X, BASE >::GetAlignment ( ) const

inlinevirtual

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.

Reimplemented in ChaCha_Policy, ChaChaTLS_Policy, XChaCha20_Policy, and PanamaCipherPolicy< B >.

Definition at line 220 of file strciphr.h.

◆ GetBytesPerIteration()

template<typename WT , unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>

unsigned int AdditiveCipherConcretePolicy< WT, W, X, BASE >::GetBytesPerIteration ( ) const

inlinevirtual

Provides number of bytes operated upon during an iteration.

Returns: bytes operated upon during an iteration, in bytes

See also: GetOptimalBlockSize()

Implements AdditiveCipherAbstractPolicy.

Definition at line 225 of file strciphr.h.

◆ GetIterationsToBuffer()

template<typename WT , unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>

unsigned int AdditiveCipherConcretePolicy< WT, W, X, BASE >::GetIterationsToBuffer ( ) const

inlinevirtual

Provides buffer size based on iterations.

Returns: the buffer size based on iterations, in bytes

Implements AdditiveCipherAbstractPolicy.

Definition at line 229 of file strciphr.h.

◆ OperateKeystream()

template<typename WT , unsigned int W, unsigned int X = 1, class BASE = AdditiveCipherAbstractPolicy>

virtual void AdditiveCipherConcretePolicy< WT, W, X, BASE >::OperateKeystream	(	KeystreamOperation	operation,
		byte *	output,
		const byte *	input,
		size_t	iterationCount
	)

pure virtual

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().