CFB_CipherTemplate< BASE > Class Template Reference

Base class for feedback based stream ciphers with SymmetricCipher interface. More...

Inheritance diagram for CFB_CipherTemplate< BASE >:

Public Types
typedef BASE::PolicyInterface	PolicyInterface

Public Member Functions
void	ProcessData (byte *outString, const byte *inString, size_t length)
	Apply keystream to data. More...
void	Resynchronize (const byte *iv, int length=-1)
	Resynchronize the cipher. More...
unsigned int	OptimalBlockSize () const
	Provides number of ideal bytes to process. More...
unsigned int	GetOptimalNextBlockSize () const
	Provides number of ideal bytes to process. More...
unsigned int	OptimalDataAlignment () const
	Provides number of ideal data alignment. More...
bool	IsRandomAccess () const
	Flag indicating random access. More...
bool	IsSelfInverting () const
	Determines if the cipher is self inverting. More...
std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm. More...

Detailed Description

template<class BASE>
class CFB_CipherTemplate< BASE >

Base class for feedback based stream ciphers with SymmetricCipher interface.

Template Parameters

BASE	AbstractPolicyHolder base class

Definition at line 567 of file strciphr.h.

Member Function Documentation

ProcessData()

template<class BASE >

void CFB_CipherTemplate< BASE >::ProcessData	(	byte *	outString,
		const byte *	inString,
		size_t	length
	)

Apply keystream to data.

Parameters

outString	a buffer to write the transformed data
inString	a buffer to read the data
length	the size of the buffers, in bytes

This is the primary method to operate a stream cipher. For example:

    size_t size = 30;
    byte plain[size] = "Do or do not; there is no try";
    byte cipher[size];
    ...
    ChaCha20 chacha(key, keySize);
    chacha.ProcessData(cipher, plain, size);

You should use distinct buffers for inString and outString. If the buffers are the same, then the data will be copied to an internal buffer to avoid GCC alias violations. The internal copy will impact performance.

See also

Issue 1088, 36% loss of performance with AES, Issue 1010, HIGHT cipher troubles with FileSource

Resynchronize()

template<class BASE >

void CFB_CipherTemplate< BASE >::Resynchronize	(	const byte *	iv,
		int	length = -1
	)

Resynchronize the cipher.

Parameters

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

OptimalBlockSize()

template<class BASE >

unsigned int CFB_CipherTemplate< BASE >::OptimalBlockSize ( ) const

inline

Provides number of ideal bytes to process.

Returns

the ideal number of bytes to process

Internally, the default implementation returns GetBytesPerIteration()

See also

GetBytesPerIteration() and GetOptimalNextBlockSize()

Definition at line 603 of file strciphr.h.

GetOptimalNextBlockSize()

template<class BASE >

unsigned int CFB_CipherTemplate< BASE >::GetOptimalNextBlockSize ( ) const

inline

Provides number of ideal bytes to process.

Returns

the ideal number of bytes to process

Internally, the default implementation returns remaining unprocessed bytes

See also

GetBytesPerIteration() and OptimalBlockSize()

Definition at line 609 of file strciphr.h.

OptimalDataAlignment()

template<class BASE >

unsigned int CFB_CipherTemplate< BASE >::OptimalDataAlignment ( ) const

inline

Provides number of ideal data alignment.

Returns

the ideal data alignment, in bytes

See also

GetAlignment() and OptimalBlockSize()

Definition at line 614 of file strciphr.h.

IsRandomAccess()

template<class BASE >

bool CFB_CipherTemplate< BASE >::IsRandomAccess ( ) const

inline

Flag indicating random access.

Returns

true if the cipher is seekable, false otherwise

See also

Seek()

Definition at line 619 of file strciphr.h.

IsSelfInverting()

template<class BASE >

bool CFB_CipherTemplate< BASE >::IsSelfInverting ( ) const

inline

Determines if the cipher is self inverting.

Returns

true if the stream cipher is self inverting, false otherwise

Definition at line 623 of file strciphr.h.

AlgorithmProvider()

template<class BASE >

std::string CFB_CipherTemplate< BASE >::AlgorithmProvider ( ) const

inline

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.

Definition at line 639 of file strciphr.h.

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

• strciphr.h