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CTR_ModePolicy Class Reference

CTR block cipher mode of operation. More...

#include <modes.h>

Inheritance diagram for CTR_ModePolicy:
ModePolicyCommonTemplate< AdditiveCipherAbstractPolicy > CipherModeBase AdditiveCipherAbstractPolicy SymmetricCipher SimpleKeyingInterface StreamTransformation Algorithm Clonable AbstractPolicyHolder< AdditiveCipherAbstractPolicy, CTR_ModePolicy > AdditiveCipherTemplate< AbstractPolicyHolder< AdditiveCipherAbstractPolicy, CTR_ModePolicy > > ConcretePolicyHolder< Empty, AdditiveCipherTemplate< AbstractPolicyHolder< AdditiveCipherAbstractPolicy, CTR_ModePolicy > > > CipherModeFinalTemplate_ExternalCipher< ConcretePolicyHolder< Empty, AdditiveCipherTemplate< AbstractPolicyHolder< AdditiveCipherAbstractPolicy, CTR_ModePolicy > > > > GCM_Base::GCTR

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
StreamTransformationRef ()
 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 ClonableClone () const
 Copies this object.
 
- Public Member Functions inherited from AdditiveCipherAbstractPolicy
virtual unsigned int GetOptimalBlockSize () const
 Provides number of ideal bytes to process.
 
virtual std::string AlgorithmProvider () const
 Retrieve the provider of this algorithm.
 

Protected Member Functions

virtual void IncrementCounterBy256 ()
 
unsigned int GetAlignment () const
 Provides data alignment requirements.
 
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 *buffer, size_t iterationCount)
 Generate the keystream.
 
bool CanOperateKeystream () const
 Flag indicating.
 
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.
 
void SeekToIteration (lword iterationCount)
 Seeks to a random position in the stream.
 
- 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 AlgorithmGetAlgorithm () 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 byteGetIVAndThrowIfInvalid (const NameValuePairs &params, size_t &size)
 Retrieves and validates the IV.
 
void AssertValidKeyLength (size_t length) const
 Validates the key length.
 

Protected Attributes

SecByteBlock m_counterArray
 
- Protected Attributes inherited from CipherModeBase
BlockCipherm_cipher
 
SecByteBlock 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 224 of file modes.h.

Constructor & Destructor Documentation

◆ ~CTR_ModePolicy()

virtual CTR_ModePolicy::~CTR_ModePolicy ( )
inlinevirtual

Definition at line 229 of file modes.h.

Member Function Documentation

◆ CanOperateKeystream()

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 240 of file modes.h.

◆ CipherIsRandomAccess()

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 230 of file modes.h.

◆ CipherResynchronize()

void CTR_ModePolicy::CipherResynchronize ( byte keystreamBuffer,
const byte iv,
size_t  length 
)
protectedvirtual

Resynchronize the cipher.

Parameters
keystreamBufferthe keystream buffer
iva byte array used to resynchronize the cipher
lengththe size of the IV array

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 163 of file modes.cpp.

◆ GetAlignment()

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 235 of file modes.h.

◆ GetBytesPerIteration()

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 236 of file modes.h.

◆ GetIterationsToBuffer()

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 237 of file modes.h.

◆ IncrementCounterBy256()

void CTR_ModePolicy::IncrementCounterBy256 ( )
protectedvirtual

Definition at line 135 of file modes.cpp.

◆ IVRequirement()

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 231 of file modes.h.

◆ OperateKeystream()

void CTR_ModePolicy::OperateKeystream ( KeystreamOperation  operation,
byte output,
const byte input,
size_t  iterationCount 
)
protectedvirtual

Operates the keystream.

Parameters
operationthe operation with additional flags
outputthe output buffer
inputthe input buffer
iterationCountthe 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()

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 140 of file modes.cpp.

◆ SeekToIteration()

void CTR_ModePolicy::SeekToIteration ( lword  iterationCount)
protectedvirtual

Seeks to a random position in the stream.

See also
CipherIsRandomAccess()

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 123 of file modes.cpp.

◆ StaticAlgorithmName()

CRYPTOPP_STATIC_CONSTEXPR const char *CRYPTOPP_API CTR_ModePolicy::StaticAlgorithmName ( )
inline

Definition at line 227 of file modes.h.

◆ WriteKeystream()

void CTR_ModePolicy::WriteKeystream ( byte keystream,
size_t  iterationCount 
)
inlineprotectedvirtual

Generate the keystream.

Parameters
keystreamthe key stream
iterationCountthe number of iterations to generate the key stream
See also
CanOperateKeystream(), OperateKeystream(), WriteKeystream()

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 238 of file modes.h.

Member Data Documentation

◆ m_counterArray

SecByteBlock CTR_ModePolicy::m_counterArray
mutableprotected

Definition at line 246 of file modes.h.


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