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...
 
- Public Member Functions inherited from HashTransformation
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...
 
- Public Member Functions inherited from 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 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.

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 message.

Precondition
COUNTOF(digest) == DigestSize() or COUNTOF(digest) == HASH::DIGESTSIZE ensures the output byte buffer is large enough for the digest.

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 message.

Reimplemented from HashTransformation.

Definition at line 17 of file trunhash.h.


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