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HashTransformation Class Reference

#include <cryptlib.h>

Inheritance diagram for HashTransformation:

Algorithm Clonable Adler32 CRC32 IteratedHashBase< T_HashWordType, HashTransformation > IteratedHashBase< word32, HashTransformation > IteratedHashBase< word64, HashTransformation > MD2 MessageAuthenticationCode PK_MessageAccumulator 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 521 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 BlockSize () const
 block size of underlying compression function, or 0 if not block based
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 532 of file cryptlib.h.

Referenced by PKCS5_PBKDF2_HMAC< T >::DeriveKey(), HashFilter::Put2(), and HMAC_Base::TruncatedFinal().

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 558 of file cryptlib.h.


The documentation for this class was generated from the following files:
Generated on Wed Jul 21 19:15:53 2004 for Crypto++ by doxygen 1.3.7-20040704