XTS block cipher mode of operation default implementation. More...

#include <xts.h>

Inheritance diagram for XTS_ModeBase:

Public Member Functions
std::string	AlgorithmName () const
	Provides the name of this algorithm.

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 n) const
	Returns a valid key length for the algorithm.

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

void	ThrowIfInvalidKeyLength (size_t length)
	Validates the key length.

unsigned int	BlockSize () const
	Provides the block size of the cipher.

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

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

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

void	ThrowIfInvalidBlockSize (size_t length)
	Validates the block size.

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

IV_Requirement	IVRequirement () const
	Minimal requirement for secure IVs.

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

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

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

void	Resynchronize (word64 sector, ByteOrder order=BIG_ENDIAN_ORDER)
	Resynchronize the cipher.

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

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

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

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

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

Public Member Functions inherited from CipherModeBase
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
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	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	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 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 void	Seek (lword pos)
	Seek to an absolute position.

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

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

Static Public Member Functions
static const char *	StaticAlgorithmName ()
	The algorithm name.

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

XTS block cipher mode of operation default implementation.

Since: Crypto++ 8.3

Definition at line 49 of file xts.h.

Constructor & Destructor Documentation

◆ ~XTS_ModeBase()

virtual XTS_ModeBase::~XTS_ModeBase ( )

inlinevirtual

Definition at line 59 of file xts.h.

Member Function Documentation

◆ StaticAlgorithmName()

static const char * XTS_ModeBase::StaticAlgorithmName ( )

inlinestatic

The algorithm name.

Returns: the algorithm name

StaticAlgorithmName returns the algorithm's name as a static member function.

Definition at line 56 of file xts.h.

◆ AlgorithmName()

std::string XTS_ModeBase::AlgorithmName ( ) const

inlinevirtual

Provides the name of this algorithm.

Returns: the standard algorithm name

The standard algorithm name can be a name like AES or AES/GCM. Some algorithms do not have standard names yet. For example, there is no standard algorithm name for Shoup's ECIES.

Note: AlgorithmName is not universally implemented yet.

Reimplemented from Algorithm.

Definition at line 61 of file xts.h.

◆ AlgorithmProvider()

std::string XTS_ModeBase::AlgorithmProvider ( ) const

inlinevirtual

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.

Since: Crypto++ 8.0

Reimplemented from CipherModeBase.

Definition at line 63 of file xts.h.

◆ MinKeyLength()

size_t XTS_ModeBase::MinKeyLength ( ) const

inlinevirtual

Returns smallest valid key length.

Returns: the minimum key length, in bytes

Reimplemented from CipherModeBase.

Definition at line 66 of file xts.h.

◆ MaxKeyLength()

size_t XTS_ModeBase::MaxKeyLength ( ) const

inlinevirtual

Returns largest valid key length.

Returns: the maximum key length, in bytes

Reimplemented from CipherModeBase.

Definition at line 68 of file xts.h.

◆ DefaultKeyLength()

size_t XTS_ModeBase::DefaultKeyLength ( ) const

inlinevirtual

Returns default key length.

Returns: the default key length, in bytes

Reimplemented from CipherModeBase.

Definition at line 70 of file xts.h.

◆ GetValidKeyLength()

size_t XTS_ModeBase::GetValidKeyLength ( size_t keylength ) const

inlinevirtual

Returns a valid key length for the algorithm.

Parameters

keylength the size of the key, in bytes

Returns: the valid key length, in bytes

keylength is provided in bytes, not bits. If keylength is less than MIN_KEYLENGTH, then the function returns MIN_KEYLENGTH. If keylength is greater than MAX_KEYLENGTH, then the function returns MAX_KEYLENGTH. if If keylength is a multiple of KEYLENGTH_MULTIPLE, then keylength is returned. Otherwise, the function returns a lower multiple of KEYLENGTH_MULTIPLE.

Reimplemented from CipherModeBase.

Definition at line 72 of file xts.h.

◆ IsValidKeyLength()

bool XTS_ModeBase::IsValidKeyLength ( size_t keylength ) const

inlinevirtual

Returns whether keylength is a valid key length.

Parameters

keylength the requested keylength

Returns: true if keylength is valid, false otherwise

Internally the function calls GetValidKeyLength()

Reimplemented from CipherModeBase.

Definition at line 74 of file xts.h.

◆ ThrowIfInvalidKeyLength()

void XTS_ModeBase::ThrowIfInvalidKeyLength ( size_t length )

Validates the key length.

Parameters

length the size of the keying material, in bytes

Exceptions

InvalidKeyLength if the key length is invalid

Definition at line 208 of file xts.cpp.

◆ BlockSize()

unsigned int XTS_ModeBase::BlockSize ( ) const

inline

Provides the block size of the cipher.

Returns: the block size of the cipher, in bytes

Definition at line 84 of file xts.h.

◆ GetOptimalBlockSize()

unsigned int XTS_ModeBase::GetOptimalBlockSize ( ) const

inline

Provides the input block size most efficient for this cipher.

Returns: The input block size that is most efficient for the cipher

The base class implementation returns MandatoryBlockSize().

Note: Optimal input length is n * OptimalBlockSize() - GetOptimalBlockSizeUsed() for any n > 0.

Definition at line 93 of file xts.h.

◆ MinLastBlockSize()

unsigned int XTS_ModeBase::MinLastBlockSize ( ) const

inlinevirtual

Provides the size of the last block.

Returns: the minimum size of the last block

MinLastBlockSize() returns the minimum size of the last block. 0 indicates the last block is not special.

MandatoryBlockSize() enlists one of two behaviors. First, if MandatoryBlockSize() returns 1, then the cipher can be streamed and ProcessData() is called with the tail bytes. Second, if MandatoryBlockSize() returns non-0, then the string of bytes is padded to MandatoryBlockSize() according to the padding mode. Then, ProcessData() is called with the padded string of bytes.

Some authenticated encryption modes are not expressed well with MandatoryBlockSize() and MinLastBlockSize(). For example, AES/OCB uses 16-byte blocks (MandatoryBlockSize = 16) and the last block requires special processing (MinLastBlockSize = 0). However, 0 is a valid last block size for OCB and the special processing is custom padding, and not standard PKCS padding. In response an unambiguous IsLastBlockSpecial() was added.

See also: ProcessData, ProcessLastBlock, MandatoryBlockSize, MinLastBlockSize, BlockPaddingSchemeDef, IsLastBlockSpecial

Reimplemented from StreamTransformation.

Definition at line 95 of file xts.h.

◆ OptimalDataAlignment()

unsigned int XTS_ModeBase::OptimalDataAlignment ( ) const

inlinevirtual

Provides input and output data alignment for optimal performance.

Returns: the input data alignment that provides optimal performance

See also: GetAlignment() and OptimalBlockSize()

Reimplemented from CipherModeBase.

Definition at line 97 of file xts.h.

◆ ThrowIfInvalidBlockSize()

void XTS_ModeBase::ThrowIfInvalidBlockSize ( size_t length )

Validates the block size.

Parameters

length the block size of the cipher, in bytes

Exceptions

InvalidArgument if the block size is invalid

If CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS is 0, then CIPHER must be a 16-byte block cipher. If CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS is non-zero then CIPHER can be 16, 32, 64, or 128-byte block cipher.

Definition at line 195 of file xts.cpp.

◆ SetKey()

void XTS_ModeBase::SetKey	(	const byte *	key,
		size_t	length,
		const NameValuePairs &	params = g_nullNameValuePairs )

virtual

Sets or reset the key of this object.

Parameters

key	the key to use when keying the object
length	the size of the key, in bytes
params	additional initialization parameters to configure this object

Reimplemented from SimpleKeyingInterface.

Definition at line 215 of file xts.cpp.

◆ IVRequirement()

IV_Requirement XTS_ModeBase::IVRequirement ( ) const

inlinevirtual

Minimal requirement for secure IVs.

Returns: the secure IV requirement of the algorithm

Implements CipherModeBase.

Definition at line 110 of file xts.h.

◆ Resynchronize() [1/2]

void XTS_ModeBase::Resynchronize	(	const byte *	iv,
		int	ivLength = -1 )

virtual

Resynchronize with an IV.

Parameters

iv	the initialization vector
ivLength	the size of the initialization vector, in bytes

Resynchronize() resynchronizes with an IV provided by the caller. ivLength=-1 means use IVSize().

Exceptions

NotImplemented() if the object does not support resynchronization

Reimplemented from BlockOrientedCipherModeBase.

Definition at line 231 of file xts.cpp.

◆ ProcessData()

void XTS_ModeBase::ProcessData	(	byte *	outString,
		const byte *	inString,
		size_t	length )

virtual

Encrypt or decrypt an array of bytes.

Parameters

outString	the output byte buffer
inString	the input byte buffer
length	the size of the input and output byte buffers, in bytes

ProcessData is called with a string of bytes whose size depends on MandatoryBlockSize. Either inString == outString, or they must not overlap.

See also: ProcessData, ProcessLastBlock, MandatoryBlockSize, MinLastBlockSize, BlockPaddingSchemeDef, IsLastBlockSpecial

Implements StreamTransformation.

Definition at line 261 of file xts.cpp.

◆ ProcessLastBlock()

size_t XTS_ModeBase::ProcessLastBlock	(	byte *	outString,
		size_t	outLength,
		const byte *	inString,
		size_t	inLength )

virtual

Encrypt or decrypt the last block of data.

Parameters

outString	the output byte buffer
outLength	the size of the output byte buffer, in bytes
inString	the input byte buffer
inLength	the size of the input byte buffer, in bytes

Returns: the number of bytes used in outString

ProcessLastBlock is used when the last block of data is special and requires handling by the cipher. The current implementation provides an output buffer with a size inLength+2*MandatoryBlockSize(). The return value allows the cipher to expand cipher text during encryption or shrink plain text during decryption.

This member function is used by CBC-CTS and OCB modes.

See also: ProcessData, ProcessLastBlock, MandatoryBlockSize, MinLastBlockSize, BlockPaddingSchemeDef, IsLastBlockSpecial

Reimplemented from StreamTransformation.

Definition at line 373 of file xts.cpp.

◆ Resynchronize() [2/2]

void XTS_ModeBase::Resynchronize	(	word64	sector,
		ByteOrder	order = BIG_ENDIAN_ORDER )

Resynchronize the cipher.

Parameters

sector	a 64-bit sector number
order	the endian order the word should be written

The Resynchronize() overload was provided for API compatibility with the IEEE P1619 paper.

Definition at line 238 of file xts.cpp.

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

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ~XTS_ModeBase()

Member Function Documentation

◆ StaticAlgorithmName()

◆ AlgorithmName()

◆ AlgorithmProvider()

◆ MinKeyLength()

◆ MaxKeyLength()

◆ DefaultKeyLength()

◆ GetValidKeyLength()

◆ IsValidKeyLength()

◆ ThrowIfInvalidKeyLength()

◆ BlockSize()

◆ GetOptimalBlockSize()

◆ MinLastBlockSize()

◆ OptimalDataAlignment()

◆ ThrowIfInvalidBlockSize()

◆ SetKey()

◆ IVRequirement()

◆ Resynchronize() [1/2]

◆ ProcessData()

◆ ProcessLastBlock()

◆ Resynchronize() [2/2]