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HashTransformation Class Reference

#include <cryptlib.h>

Inheritance diagram for HashTransformation:

Algorithm Clonable Adler32 CRC32 MD2 MessageAuthenticationCode PK_MessageAccumulator SapphireHash TruncatedHashTemplate< T > List of all members.

Detailed Description

interface for hash functions and data processing part of MACs

HashTransformation objects are stateful. They are created in an initial state, change state as Update() is called, and return to the initial state when Final() is called. This interface allows a large message to be hashed in pieces by calling Update() on each piece followed by calling Final().

Definition at line 498 of file cryptlib.h.

Public Member Functions

virtual void Update (const byte *input, unsigned int length)=0
 process more input

virtual byte * CreateUpdateSpace (unsigned int &size)
 request space to write input into

virtual void Final (byte *digest)
 compute hash for current message, then restart for a new message

virtual void Restart ()
 discard the current state, and restart with a new message

virtual unsigned int DigestSize () const =0
 size of the hash returned by Final()

virtual unsigned int OptimalBlockSize () const
 input to Update() should have length a multiple of this for optimal speed

virtual unsigned int OptimalDataAlignment () const
 returns how input should be aligned for optimal performance

virtual void CalculateDigest (byte *digest, const byte *input, unsigned int length)
 use this if your input is in one piece and you don't want to call Update() and Final() separately

virtual bool Verify (const byte *digest)
 verify that digest is a valid digest for the current message, then reinitialize the object

virtual bool VerifyDigest (const byte *digest, const byte *input, unsigned int length)
 use this if your input is in one piece and you don't want to call Update() and Verify() separately

virtual void TruncatedFinal (byte *digest, unsigned int digestSize)=0
 truncated version of Final()

virtual void CalculateTruncatedDigest (byte *digest, unsigned int digestSize, const byte *input, unsigned int length)
 truncated version of CalculateDigest()

virtual bool TruncatedVerify (const byte *digest, unsigned int digestLength)
 truncated version of Verify()

virtual bool VerifyTruncatedDigest (const byte *digest, unsigned int digestLength, const byte *input, unsigned int length)
 truncated version of VerifyDigest()

virtual std::string AlgorithmName () const
 returns name of this algorithm, not universally implemented yet

virtual ClonableClone () const
 this is not implemented by most classes yet


Protected Member Functions

void ThrowIfInvalidTruncatedSize (unsigned int size) const


Member Function Documentation

virtual void HashTransformation::Final byte *  digest  )  [inline, virtual]
 

compute hash for current message, then restart for a new message

Precondition:
size of digest == DigestSize().

Definition at line 509 of file cryptlib.h.

virtual bool HashTransformation::Verify const byte *  digest  )  [inline, virtual]
 

verify that digest is a valid digest for the current message, then reinitialize the object

Default implementation is to call Final() and do a bitwise comparison between its output and digest.

Definition at line 532 of file cryptlib.h.


The documentation for this class was generated from the following files:
Generated on Fri Aug 13 09:56:58 2004 for Crypto++ by doxygen 1.3.7