IETF XChaCha20 stream cipher implementation. More...

#include <chacha.h>

Inheritance diagram for XChaCha20_Policy:

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

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

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

bool	CipherIsRandomAccess () const
	Flag indicating random access.

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

unsigned int	GetAlignment () const
	Provides data alignment requirements.

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

std::string	AlgorithmName () const

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

	CRYPTOPP_CONSTANT (ROUNDS=20)

	CRYPTOPP_CONSTANT (KEY=16)

Protected Attributes
FixedSizeAlignedSecBlock< word32, 16+8 >	m_state

unsigned int	m_counter

unsigned int	m_rounds

Additional Inherited Members
Public Types inherited from AdditiveCipherConcretePolicy< word32, 16 >
typedef word32	WordType
	Word type for the cipher.

Public Member Functions inherited from AdditiveCipherConcretePolicy< word32, 16 >
	CRYPTOPP_CONSTANT (BYTES_PER_ITERATION=sizeof(WordType) *W)
	Number of bytes for an iteration.

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.

Public Member Functions inherited from AdditiveCipherAbstractPolicy
virtual void	WriteKeystream (byte *keystream, size_t iterationCount)
	Generate the keystream.

Detailed Description

IETF XChaCha20 stream cipher implementation.

Since: Crypto++ 8.1

Definition at line 180 of file chacha.h.

Constructor & Destructor Documentation

◆ ~XChaCha20_Policy()

virtual XChaCha20_Policy::~XChaCha20_Policy ( )

inlinevirtual

Definition at line 183 of file chacha.h.

◆ XChaCha20_Policy()

XChaCha20_Policy::XChaCha20_Policy ( )

inline

Definition at line 184 of file chacha.h.

Member Function Documentation

◆ AlgorithmName()

std::string XChaCha20_Policy::AlgorithmName ( ) const

protected

Definition at line 478 of file chacha.cpp.

◆ AlgorithmProvider()

std::string XChaCha20_Policy::AlgorithmProvider ( ) const

protectedvirtual

Retrieve the provider of this algorithm.

Returns: the algorithm provider

The algorithm provider can be a name like "C++", "SSE", "NEON", "AESNI", "ARMv8" and "Power8". C++ is standard C++ code. Other labels, like SSE, usually indicate a specialized implementation using instructions from a higher instruction set architecture (ISA). Future labels may include external hardware like a hardware security module (HSM).

Generally speaking Wei Dai's original IA-32 ASM code falls under "SSE2". Labels like "SSSE3" and "SSE4.1" follow after Wei's code and use intrinsics instead of ASM.

Algorithms which combine different instructions or ISAs provide the dominant one. For example on x86 AES/GCM returns "AESNI" rather than "CLMUL" or "AES+SSE4.1" or "AES+CLMUL" or "AES+SSE4.1+CLMUL".

Note: Provider is not universally implemented yet.

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 483 of file chacha.cpp.

◆ CipherIsRandomAccess()

bool XChaCha20_Policy::CipherIsRandomAccess ( ) const

inlineprotectedvirtual

Flag indicating random access.

Returns: true if the cipher is seekable, false otherwise

See also: SeekToIteration()

Implements AdditiveCipherAbstractPolicy.

Definition at line 190 of file chacha.h.

◆ CipherResynchronize()

void XChaCha20_Policy::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 513 of file chacha.cpp.

◆ CipherSetKey()

void XChaCha20_Policy::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 488 of file chacha.cpp.

◆ GetAlignment()

unsigned int XChaCha20_Policy::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 AdditiveCipherConcretePolicy< word32, 16 >.

Definition at line 551 of file chacha.cpp.

◆ GetOptimalBlockSize()

unsigned int XChaCha20_Policy::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 556 of file chacha.cpp.

◆ OperateKeystream()

void XChaCha20_Policy::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().

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

Implements AdditiveCipherConcretePolicy< word32, 16 >.

Definition at line 561 of file chacha.cpp.

◆ SeekToIteration()

void XChaCha20_Policy::SeekToIteration ( lword iterationCount )

protectedvirtual

Seeks to a random position in the stream.

See also: CipherIsRandomAccess()

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 544 of file chacha.cpp.

Member Data Documentation

◆ m_counter

unsigned int XChaCha20_Policy::m_counter

protected

Definition at line 199 of file chacha.h.

◆ m_rounds

unsigned int XChaCha20_Policy::m_rounds

protected

Definition at line 199 of file chacha.h.

◆ m_state

FixedSizeAlignedSecBlock<word32, 16+8> XChaCha20_Policy::m_state

protected

Definition at line 198 of file chacha.h.

The documentation for this class was generated from the following files:

G:/work/subversion/scol-technologies/trunk/scol/plugins/security/cryptopp/chacha.h
G:/work/subversion/scol-technologies/trunk/scol/plugins/security/cryptopp/chacha.cpp

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ~XChaCha20_Policy()

◆ XChaCha20_Policy()

Member Function Documentation

◆ AlgorithmName()

◆ AlgorithmProvider()

◆ CipherIsRandomAccess()

◆ CipherResynchronize()

◆ CipherSetKey()

◆ GetAlignment()

◆ GetOptimalBlockSize()

◆ OperateKeystream()

◆ SeekToIteration()

Member Data Documentation

◆ m_counter

◆ m_rounds

◆ m_state