OFB block cipher mode of operation. More...

#include <modes.h>

Inheritance diagram for OFB_ModePolicy:

Public Member Functions
CRYPTOPP_STATIC_CONSTEXPR const char *CRYPTOPP_API	StaticAlgorithmName ()

bool	CipherIsRandomAccess () const
	Flag indicating random access.

IV_Requirement	IVRequirement () const
	Minimal requirement for secure IVs.

Public Member Functions inherited from CipherModeBase
std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm.

size_t	MinKeyLength () const
	Returns smallest valid key length.

size_t	MaxKeyLength () const
	Returns largest valid key length.

size_t	DefaultKeyLength () const
	Returns default key length.

size_t	GetValidKeyLength (size_t keylength) const
	Returns a valid key length for the algorithm.

bool	IsValidKeyLength (size_t keylength) const
	Returns whether keylength is a valid key length.

unsigned int	OptimalDataAlignment () const
	Provides input and output data alignment for optimal performance.

unsigned int	IVSize () const
	Returns length of the IV accepted by this object.

void	SetCipher (BlockCipher &cipher)
	Set external block cipher.

void	SetCipherWithIV (BlockCipher &cipher, const byte *iv, int feedbackSize=0)
	Set external block cipher and IV.

Public Member Functions inherited from SimpleKeyingInterface
virtual void	SetKey (const byte *key, size_t length, const NameValuePairs &params=g_nullNameValuePairs)
	Sets or reset the key of this object.

void	SetKeyWithRounds (const byte *key, size_t length, int rounds)
	Sets or reset the key of this object.

void	SetKeyWithIV (const byte key, size_t length, const byte iv, size_t ivLength)
	Sets or reset the key of this object.

void	SetKeyWithIV (const byte key, size_t length, const byte iv)
	Sets or reset the key of this object.

bool	IsResynchronizable () const
	Determines if the object can be resynchronized.

bool	CanUseRandomIVs () const
	Determines if the object can use random IVs.

bool	CanUsePredictableIVs () const
	Determines if the object can use random but possibly predictable IVs.

bool	CanUseStructuredIVs () const
	Determines if the object can use structured IVs.

unsigned int	DefaultIVLength () const
	Provides the default size of an IV.

virtual unsigned int	MinIVLength () const
	Provides the minimum size of an IV.

virtual unsigned int	MaxIVLength () const
	Provides the maximum size of an IV.

virtual void	Resynchronize (const byte *iv, int ivLength=-1)
	Resynchronize with an IV.

virtual void	GetNextIV (RandomNumberGenerator &rng, byte *iv)
	Retrieves a secure IV for the next message.

Public Member Functions inherited from StreamTransformation
StreamTransformation &	Ref ()
	Provides a reference to this object.

virtual unsigned int	MandatoryBlockSize () const
	Provides the mandatory block size of the cipher.

virtual unsigned int	OptimalBlockSize () const
	Provides the input block size most efficient for this cipher.

virtual unsigned int	GetOptimalBlockSizeUsed () const
	Provides the number of bytes used in the current block when processing at optimal block size.

virtual void	ProcessData (byte outString, const byte inString, size_t length)=0
	Encrypt or decrypt an array of bytes.

virtual size_t	ProcessLastBlock (byte outString, size_t outLength, const byte inString, size_t inLength)
	Encrypt or decrypt the last block of data.

virtual unsigned int	MinLastBlockSize () const
	Provides the size of the last block.

virtual bool	IsLastBlockSpecial () const
	Determines if the last block receives special processing.

void	ProcessString (byte *inoutString, size_t length)
	Encrypt or decrypt a string of bytes.

void	ProcessString (byte outString, const byte inString, size_t length)
	Encrypt or decrypt a string of bytes.

byte	ProcessByte (byte input)
	Encrypt or decrypt a byte.

virtual bool	IsRandomAccess () const =0
	Determines whether the cipher supports random access.

virtual void	Seek (lword pos)
	Seek to an absolute position.

virtual bool	IsSelfInverting () const =0
	Determines whether the cipher is self-inverting.

virtual bool	IsForwardTransformation () const =0
	Determines if the cipher is being operated in its forward direction.

Public Member Functions inherited from Algorithm
	Algorithm (bool checkSelfTestStatus=true)
	Interface for all crypto algorithms.

virtual std::string	AlgorithmName () const
	Provides the name of this algorithm.

Public Member Functions inherited from Clonable
virtual Clonable *	Clone () const
	Copies this object.

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

virtual bool	CanOperateKeystream () const
	Flag indicating.

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

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

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

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

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

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

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

Protected Member Functions inherited from CipherModeBase
unsigned int	BlockSize () const

virtual void	SetFeedbackSize (unsigned int feedbackSize)

virtual void	ResizeBuffers ()

Protected Member Functions inherited from SymmetricCipher
const Algorithm &	GetAlgorithm () const
	Returns the base class Algorithm.

Protected Member Functions inherited from SimpleKeyingInterface
virtual void	UncheckedSetKey (const byte *key, unsigned int length, const NameValuePairs &params)=0
	Sets the key for this object without performing parameter validation.

void	ThrowIfInvalidKeyLength (size_t length)
	Validates the key length.

void	ThrowIfResynchronizable ()
	Validates the object.

void	ThrowIfInvalidIV (const byte *iv)
	Validates the IV.

size_t	ThrowIfInvalidIVLength (int length)
	Validates the IV length.

const byte *	GetIVAndThrowIfInvalid (const NameValuePairs &params, size_t &size)
	Retrieves and validates the IV.

void	AssertValidKeyLength (size_t length) const
	Validates the key length.

Additional Inherited Members
Public Types inherited from SimpleKeyingInterface
enum	IV_Requirement { UNIQUE_IV = 0 , RANDOM_IV , UNPREDICTABLE_RANDOM_IV , INTERNALLY_GENERATED_IV , NOT_RESYNCHRONIZABLE }
	Secure IVs requirements as enumerated values. More...

Protected Attributes inherited from CipherModeBase
BlockCipher *	m_cipher

SecByteBlock	m_register

Detailed Description

OFB block cipher mode of operation.

Definition at line 208 of file modes.h.

Member Function Documentation

◆ CipherIsRandomAccess()

bool OFB_ModePolicy::CipherIsRandomAccess ( ) const

inlinevirtual

Flag indicating random access.

Returns: true if the cipher is seekable, false otherwise

See also: SeekToIteration()

Implements AdditiveCipherAbstractPolicy.

Definition at line 213 of file modes.h.

◆ CipherResynchronize()

void OFB_ModePolicy::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 114 of file modes.cpp.

◆ GetBytesPerIteration()

unsigned int OFB_ModePolicy::GetBytesPerIteration ( ) const

inlineprotectedvirtual

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 217 of file modes.h.

◆ GetIterationsToBuffer()

unsigned int OFB_ModePolicy::GetIterationsToBuffer ( ) const

inlineprotectedvirtual

Provides buffer size based on iterations.

Returns: the buffer size based on iterations, in bytes

Implements AdditiveCipherAbstractPolicy.

Definition at line 218 of file modes.h.

◆ IVRequirement()

IV_Requirement OFB_ModePolicy::IVRequirement ( ) const

inlinevirtual

Minimal requirement for secure IVs.

Returns: the secure IV requirement of the algorithm

Implements CipherModeBase.

Definition at line 214 of file modes.h.

◆ StaticAlgorithmName()

CRYPTOPP_STATIC_CONSTEXPR const char *CRYPTOPP_API OFB_ModePolicy::StaticAlgorithmName ( )

inline

Definition at line 211 of file modes.h.

◆ WriteKeystream()

void OFB_ModePolicy::WriteKeystream	(	byte *	keystream,
		size_t	iterationCount
	)

protectedvirtual

Generate the keystream.

Parameters

keystream	the key stream
iterationCount	the number of iterations to generate the key stream

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

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 101 of file modes.cpp.

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

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

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ CipherIsRandomAccess()

◆ CipherResynchronize()

◆ GetBytesPerIteration()

◆ GetIterationsToBuffer()

◆ IVRequirement()

◆ StaticAlgorithmName()

◆ WriteKeystream()