Null hash. More...

#include <trunhash.h>

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

virtual void	Update (const byte *input, size_t length)=0
	Updates a hash with additional input. 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...

virtual unsigned int	DigestSize () const =0
	Provides the digest size of 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	TruncatedFinal (byte *digest, size_t digestSize)=0
	Computes 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	TruncatedVerify (const byte *digest, size_t digestLength)
	Verifies 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...

virtual std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm. More...

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

Detailed Description

Null hash.

A null hash that conforms to HashTransformation interface

Definition at line 15 of file trunhash.h.

Member Function Documentation

◆ Update()

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

inlinevirtual

Updates a hash with additional input.

Parameters

input	the additional input as a buffer
length	the size of the buffer, in bytes

Implements HashTransformation.

Definition at line 18 of file trunhash.h.

◆ DigestSize()

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 20 of file trunhash.h.

◆ TruncatedFinal()

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

inlinevirtual

Computes the hash of the current message.

Parameters

digest	a pointer to the buffer to receive the hash
digestSize	the size of the truncated digest, in bytes

TruncatedFinal() calls Final() and then copies digestSize bytes to digest. The hash is restarted the hash for the next message.

Precondition: COUNTOF(digest) <= DigestSize() or COUNTOF(digest) <= HASH::DIGESTSIZE ensures the output byte buffer is a valid size.

Implements HashTransformation.

Definition at line 22 of file trunhash.h.

◆ TruncatedVerify()

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

inlinevirtual

Verifies the hash of the current message.

Parameters

digest	a pointer to the buffer of an existing hash
digestLength	the size of the truncated hash, in bytes

Returns: true if the existing hash matches the computed hash, false otherwise

Exceptions

InvalidArgument() 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.

Precondition: digestLength <= DigestSize() or digestLength <= HASH::DIGESTSIZE ensures the input byte buffer is a valid size.

Reimplemented from HashTransformation.

Definition at line 24 of file trunhash.h.

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

trunhash.h

Public Member Functions

Detailed Description

Member Function Documentation

◆ Update()

◆ DigestSize()

◆ TruncatedFinal()

◆ TruncatedVerify()