CTR block cipher mode of operation. More...

#include <modes.h>

Inheritance diagram for CTR_ModePolicy:

Collaboration diagram for CTR_ModePolicy:

Public Member Functions
CRYPTOPP_STATIC_CONSTEXPR const char *CRYPTOPP_API	StaticAlgorithmName ()

virtual	~CTR_ModePolicy ()

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

IV_Requirement	IVRequirement () const
	Minimal requirement for secure IVs. More...

Public Member Functions inherited from CipherModeBase
virtual	~CipherModeBase ()

size_t	MinKeyLength () const
	Returns smallest valid key length. More...

size_t	MaxKeyLength () const
	Returns largest valid key length. More...

size_t	DefaultKeyLength () const
	Returns default key length. More...

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

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

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

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

void	SetCipher (BlockCipher &cipher)

void	SetCipherWithIV (BlockCipher &cipher, const byte *iv, int feedbackSize=0)

Public Member Functions inherited from SimpleKeyingInterface
virtual	~SimpleKeyingInterface ()

virtual void	SetKey (const byte *key, size_t length, const NameValuePairs &params=g_nullNameValuePairs)
	Sets or reset the key of this object. More...

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

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

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

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

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

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

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

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

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

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

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

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

Public Member Functions inherited from StreamTransformation
virtual	~StreamTransformation ()

StreamTransformation &	Ref ()
	Provides a reference to this object. More...

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

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

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

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

virtual void	ProcessLastBlock (byte outString, const byte inString, size_t length)
	Encrypt or decrypt the last block of data. More...

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

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

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

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

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

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

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

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

Public Member Functions inherited from Algorithm
virtual	~Algorithm ()

	Algorithm (bool checkSelfTestStatus=true)
	Interface for all crypto algorithms. More...

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

Public Member Functions inherited from Clonable
virtual	~Clonable ()

virtual Clonable *	Clone () const
	Copies this object. More...

Public Member Functions inherited from AdditiveCipherAbstractPolicy
virtual	~AdditiveCipherAbstractPolicy ()

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

Protected Member Functions
virtual void	IncrementCounterBy256 ()

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...

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

bool	CanOperateKeystream () const
	Flag indicating. 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...

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

Protected Member Functions inherited from CipherModeBase
	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. More...

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. More...

void	ThrowIfInvalidKeyLength (size_t length)
	Validates the key length. More...

void	ThrowIfResynchronizable ()
	Validates the object. More...

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

size_t	ThrowIfInvalidIVLength (int length)
	Validates the IV length. More...

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

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

Protected Attributes
AlignedSecByteBlock	m_counterArray

Protected Attributes inherited from CipherModeBase
BlockCipher *	m_cipher

AlignedSecByteBlock	m_register

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...

Detailed Description

CTR block cipher mode of operation.

Definition at line 160 of file modes.h.

Constructor & Destructor Documentation

virtual CTR_ModePolicy::~CTR_ModePolicy ( )

inlinevirtual

Definition at line 165 of file modes.h.

Member Function Documentation

bool CTR_ModePolicy::CanOperateKeystream ( ) const

inlineprotectedvirtual

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.

Definition at line 176 of file modes.h.

bool CTR_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 166 of file modes.h.

void CTR_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 142 of file modes.cpp.

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unsigned int CTR_ModePolicy::GetAlignment ( ) const

inlineprotectedvirtual

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 171 of file modes.h.

unsigned int CTR_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 172 of file modes.h.

unsigned int CTR_ModePolicy::GetIterationsToBuffer ( ) const

inlineprotectedvirtual

Provides buffer size based on iterations.

Returns: the buffer size based on iterations, in bytes

Implements AdditiveCipherAbstractPolicy.

Definition at line 173 of file modes.h.

void CTR_ModePolicy::IncrementCounterBy256 ( )

protectedvirtual

Reimplemented in GCM_Base::GCTR.

Definition at line 117 of file modes.cpp.

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IV_Requirement CTR_ModePolicy::IVRequirement ( ) const

inlinevirtual

Minimal requirement for secure IVs.

Returns: the secure IV requirement of the algorithm

Implements CipherModeBase.

Definition at line 167 of file modes.h.

void CTR_ModePolicy::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().