Crypto++  5.6.3
Free C++ class library of cryptographic schemes
Public Member Functions | List of all members
NullHash Class Reference
+ Inheritance diagram for NullHash:

Public Member Functions

void Update (const byte *input, size_t length)
 Updates a hash with additional input. More...
 
unsigned int DigestSize () const
 Provides the digest size of the hash. More...
 
void TruncatedFinal (byte *digest, size_t digestSize)
 Computes the hash of the current message. More...
 
bool TruncatedVerify (const byte *digest, size_t digestLength)
 Verifies the hash of the current message. More...
 
HashTransformationRef ()
 Provides a reference to this object. More...
 
virtual byte * CreateUpdateSpace (size_t &size)
 Request space which can be written into by the caller. More...
 
virtual void Final (byte *digest)
 Computes the hash of the current message. More...
 
virtual void Restart ()
 Restart the hash. More...
 
unsigned int TagSize () const
 Provides the tag size of the hash. More...
 
virtual unsigned int BlockSize () const
 Provides the block size of the compression function. More...
 
virtual unsigned int OptimalBlockSize () const
 Provides the input block size most efficient for this hash. More...
 
virtual unsigned int OptimalDataAlignment () const
 Provides input and output data alignment for optimal performance. More...
 
virtual void CalculateDigest (byte *digest, const byte *input, size_t length)
 Updates the hash with additional input and computes the hash of the current message. More...
 
virtual bool Verify (const byte *digest)
 Verifies the hash of the current message. More...
 
virtual bool VerifyDigest (const byte *digest, const byte *input, size_t length)
 Updates the hash with additional input and verifies the hash of the current message. More...
 
virtual void CalculateTruncatedDigest (byte *digest, size_t digestSize, const byte *input, size_t length)
 Updates the hash with additional input and computes the hash of the current message. More...
 
virtual bool VerifyTruncatedDigest (const byte *digest, size_t digestLength, const byte *input, size_t length)
 Updates the hash with additional input and verifies the hash of the current message. More...
 
virtual std::string AlgorithmName () const
 Provides the name of this algorithm. More...
 
virtual ClonableClone () const
 Copies this object. More...
 

Detailed Description

Definition at line 8 of file trunhash.h.

Member Function Documentation

void NullHash::Update ( const byte *  input,
size_t  length 
)
inlinevirtual

Updates a hash with additional input.

Parameters
inputthe additional input as a buffer
lengththe size of the buffer, in bytes

Implements HashTransformation.

Definition at line 11 of file trunhash.h.

unsigned int NullHash::DigestSize ( ) const
inlinevirtual

Provides the digest size of the hash.

Returns
the digest size of the hash.

Calls to Final() require a buffer that is equal to (or greater than) DigestSize().

Implements HashTransformation.

Definition at line 13 of file trunhash.h.

void NullHash::TruncatedFinal ( byte *  digest,
size_t  digestSize 
)
inlinevirtual

Computes the hash of the current message.

Parameters
digesta pointer to the buffer to receive the hash
digestSizethe size of the truncated digest, in bytes

TruncatedFinal() call Final() and then copies digestSize bytes to digest

TruncatedFinal() restarts the hash for the next nmessage.

Implements HashTransformation.

Definition at line 15 of file trunhash.h.

bool NullHash::TruncatedVerify ( const byte *  digest,
size_t  digestLength 
)
inlinevirtual

Verifies the hash of the current message.

Parameters
digesta pointer to the buffer of an existing hash
digestLengththe size of the truncated hash, in bytes
Returns
true if the existing hash matches the computed hash, false otherwise
Exceptions
ThrowIfInvalidTruncatedSize()if digestLength exceeds DigestSize()

TruncatedVerify() is a truncated version of Verify(). It can operate on a buffer smaller than DigestSize(). However, digestLength cannot exceed DigestSize().

Verify() performs a bitwise compare on the buffers using VerifyBufsEqual(), which is a constant time comparison function. digestLength cannot exceed DigestSize().

TruncatedVerify() restarts the hash for the next nmessage.

Reimplemented from HashTransformation.

Definition at line 17 of file trunhash.h.

HashTransformation& HashTransformation::Ref ( )
inlineinherited

Provides a reference to this object.

Returns
A reference to this object

Useful for passing a temporary object to a function that takes a non-const reference

Definition at line 864 of file cryptlib.h.

virtual byte* HashTransformation::CreateUpdateSpace ( size_t &  size)
inlinevirtualinherited

Request space which can be written into by the caller.

Parameters
sizethe requested size of the buffer

The purpose of this method is to help avoid extra memory allocations.

size is an IN and OUT parameter and used as a hint. When the call is made, size is the requested size of the buffer. When the call returns, size is the size of the array returned to the caller.

The base class implementation sets size to 0 and returns NULL.

Note
Some objects, like ArraySink, cannot create a space because its fixed. In the case of

Definition at line 879 of file cryptlib.h.

virtual void HashTransformation::Final ( byte *  digest)
inlinevirtualinherited

Computes the hash of the current message.

Parameters
digesta pointer to the buffer to receive the hash

digest must be equal to (or greater than) DigestSize(). Final() restarts the hash for a new message.

Definition at line 885 of file cryptlib.h.

References Name::DigestSize().

Referenced by DefaultDecryptor::DefaultDecryptor(), DefaultEncryptor::DefaultEncryptor(), PKCS5_PBKDF2_HMAC< T >::DeriveKey(), RandomPool::IncorporateEntropy(), PKCS_EncryptionPaddingScheme::MaxUnpaddedLength(), and HMAC_Base::TruncatedFinal().

virtual void HashTransformation::Restart ( )
inlinevirtualinherited

Restart the hash.

Discards the current state, and restart for a new message

Reimplemented in TruncatedHashTemplate< T >, AuthenticatedSymmetricCipherBase, SHA3, and HMAC_Base.

Definition at line 890 of file cryptlib.h.

References Name::DigestSize().

Referenced by Gunzip::Gunzip(), HMAC_Base::Restart(), and ZlibDecompressor::ZlibDecompressor().

unsigned int HashTransformation::TagSize ( ) const
inlineinherited

Provides the tag size of the hash.

Returns
the tag size of the hash.

Same as DigestSize().

Definition at line 901 of file cryptlib.h.

References Name::DigestSize().

virtual unsigned int HashTransformation::BlockSize ( ) const
inlinevirtualinherited

Provides the block size of the compression function.

Returns
the block size of the compression function, in bytes

BlockSize() will return 0 if the hash is not block based. For example, SHA3 is a recursive hash (not an iterative hash), and it does not have a block size.

Reimplemented in VMAC_Base, and Weak::MD2.

Definition at line 907 of file cryptlib.h.

Referenced by CBC_MAC_Base::DigestSize(), HMAC_Base::DigestSize(), HMAC_Base::TruncatedFinal(), CBC_MAC_Base::TruncatedFinal(), and HMAC_Base::UncheckedSetKey().

virtual unsigned int HashTransformation::OptimalBlockSize ( ) const
inlinevirtualinherited

Provides the input block size most efficient for this hash.

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

The base class implemnetation returns MandatoryBlockSize().

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

Reimplemented in CMAC_Base, and HMAC_Base.

Definition at line 914 of file cryptlib.h.

unsigned int HashTransformation::OptimalDataAlignment ( ) const
virtualinherited

Provides input and output data alignment for optimal performance.

Returns
the input data alignment that provides optimal performance

Reimplemented in GCM_Base, EAX_Base, CCM_Base, VMAC_Base, CMAC_Base, and SHA3.

Definition at line 242 of file cryptlib.cpp.

virtual void HashTransformation::CalculateDigest ( byte *  digest,
const byte *  input,
size_t  length 
)
inlinevirtualinherited

Updates the hash with additional input and computes the hash of the current message.

Parameters
digesta pointer to the buffer to receive the hash
inputthe additional input as a buffer
lengththe size of the buffer, in bytes

Use this if your input is in one piece and you don't want to call Update() and Final() separately

CalculateDigest() restarts the hash for the next nmessage.

Definition at line 927 of file cryptlib.h.

Referenced by HKDF< T >::DeriveKey(), PKCS5_PBKDF2_HMAC< T >::DeriveKey(), and OAEP_Base::MaxUnpaddedLength().

virtual bool HashTransformation::Verify ( const byte *  digest)
inlinevirtualinherited

Verifies the hash of the current message.

Parameters
digesta pointer to the buffer of an existing hash
Returns
true if the existing hash matches the computed hash, false otherwise
Exceptions
ThrowIfInvalidTruncatedSize()if the existing hash's size exceeds DigestSize()

Calls to Verify() require a buffer that is equal to (or greater than) DigestSize().

Verify() performs a bitwise compare on the buffers using VerifyBufsEqual(), which is a constant time comparison function. digestLength cannot exceed DigestSize().

Verify() restarts the hash for the next nmessage.

Definition at line 938 of file cryptlib.h.

References Name::DigestSize().

Referenced by Gunzip::Gunzip(), and ZlibDecompressor::ZlibDecompressor().

virtual bool HashTransformation::VerifyDigest ( const byte *  digest,
const byte *  input,
size_t  length 
)
inlinevirtualinherited

Updates the hash with additional input and verifies the hash of the current message.

Parameters
digesta pointer to the buffer of an existing hash
inputthe additional input as a buffer
lengththe size of the buffer, in bytes
Returns
true if the existing hash matches the computed hash, false otherwise
Exceptions
ThrowIfInvalidTruncatedSize()if the existing hash's size exceeds DigestSize()

Use this if your input is in one piece and you don't want to call Update() and Verify() separately

VerifyDigest() performs a bitwise compare on the buffers using VerifyBufsEqual(), which is a constant time comparison function. digestLength cannot exceed DigestSize().

VerifyDigest() restarts the hash for the next nmessage.

Definition at line 952 of file cryptlib.h.

Referenced by OAEP_Base::MaxUnpaddedLength().

virtual void HashTransformation::CalculateTruncatedDigest ( byte *  digest,
size_t  digestSize,
const byte *  input,
size_t  length 
)
inlinevirtualinherited

Updates the hash with additional input and computes the hash of the current message.

Parameters
digesta pointer to the buffer to receive the hash
digestSizethe length of the truncated hash, in bytes
inputthe additional input as a buffer
lengththe size of the buffer, in bytes

Use this if your input is in one piece and you don't want to call Update() and CalculateDigest() separately.

CalculateTruncatedDigest() restarts the hash for the next nmessage.

Definition at line 970 of file cryptlib.h.

virtual bool HashTransformation::VerifyTruncatedDigest ( const byte *  digest,
size_t  digestLength,
const byte *  input,
size_t  length 
)
inlinevirtualinherited

Updates the hash with additional input and verifies the hash of the current message.

Parameters
digesta pointer to the buffer of an existing hash
digestLengththe size of the truncated hash, in bytes
inputthe additional input as a buffer
lengththe size of the buffer, in bytes
Returns
true if the existing hash matches the computed hash, false otherwise
Exceptions
ThrowIfInvalidTruncatedSize()if digestLength exceeds DigestSize()

Use this if your input is in one piece and you don't want to call Update() and TruncatedVerify() separately.

VerifyTruncatedDigest() is a truncated version of VerifyDigest(). It can operate on a buffer smaller than DigestSize(). However, digestLength cannot exceed DigestSize().

VerifyTruncatedDigest() restarts the hash for the next nmessage.

Definition at line 997 of file cryptlib.h.

virtual std::string Algorithm::AlgorithmName ( ) const
inlinevirtualinherited

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 in AuthenticatedSymmetricCipher, SignatureVerificationFilter, SignerFilter, AuthenticatedDecryptionFilter, HashVerificationFilter, HashFilter, StreamTransformationFilter, ClassNullRNG, BitBucket, RDSEED, DH_Domain< GROUP_PARAMETERS, COFACTOR_OPTION >, HMAC< T >, RDRAND, CRC32, GCM_Base, Adler32, EAX_Base, CCM_Base, SHA3, and VMAC_Base.

Definition at line 488 of file cryptlib.h.

Referenced by VariableRounds< 6, 2 >::StaticGetDefaultRounds().

virtual Clonable* Clonable::Clone ( ) const
inlinevirtualinherited

Copies this object.

Returns
a copy of this object
Exceptions
NotImplemented
Note
this is not implemented by most classes
See also
NotCopyable

Definition at line 464 of file cryptlib.h.


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