fr.cryptohash.DigestEngine

All Implemented Interfaces:: Digest

Direct Known Subclasses:: BLAKE224, BLAKE256, BLAKE384, BLAKE512, BMW224, BMW256, BMW384, BMW512, CubeHash224, CubeHash256, CubeHash384, CubeHash512, ECHO224, ECHO256, ECHO384, ECHO512, Groestl224, Groestl256, Groestl384, Groestl512, HAVAL128_3, HAVAL128_4, HAVAL128_5, HAVAL160_3, HAVAL160_4, HAVAL160_5, HAVAL192_3, HAVAL192_4, HAVAL192_5, HAVAL224_3, HAVAL224_4, HAVAL224_5, HAVAL256_3, HAVAL256_4, HAVAL256_5, HMAC, JH224, JH256, JH384, JH512, Keccak224, Keccak256, Keccak384, Keccak512, Luffa224, Luffa256, Luffa384, Luffa512, MD2, MD4, MD5, PANAMA, RadioGatun32, RadioGatun64, RIPEMD, RIPEMD128, RIPEMD160, SHA0, SHA1, SHA224, SHA256, SHA384, SHA512, SHAvite224, SHAvite256, SHAvite384, SHAvite512, SIMD224, SIMD256, SIMD384, SIMD512, Tiger, Tiger2, Whirlpool, Whirlpool0, Whirlpool1

public abstract class DigestEngine
extends Object
implements Digest

This class is a template which can be used to implement hash functions. It takes care of some of the API, and also provides an internal data buffer whose length is equal to the hash function internal block length.

Classes which use this template MUST provide a working Digest.getBlockLength() method even before initialization (alternatively, they may define a custom getInternalBlockLength() which does not call Digest.getBlockLength(). The Digest.getDigestLength() should also be operational from the beginning, but it is acceptable that it returns 0 while the doInit() method has not been called yet.

 ==========================(LICENSE BEGIN)============================

 Copyright (c) 2007-2010  Projet RNRT SAPHIR
 
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 a copy of this software and associated documentation files (the
 "Software"), to deal in the Software without restriction, including
 without limitation the rights to use, copy, modify, merge, publish,
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 permit persons to whom the Software is furnished to do so, subject to
 the following conditions:
 
 The above copyright notice and this permission notice shall be
 included in all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 ===========================(LICENSE END)=============================

Version:: $Revision: 229 $
Author:: Thomas Pornin <thomas.pornin@cryptolog.com>

Constructor Summary

Constructors

Constructor Description

DigestEngine()
Instantiate the engine.

Method Summary

Modifier and Type	Method	Description
`protected Digest`	`copyState(DigestEngine dest)`	This function copies the internal buffering state to some other instance of a class extending `DigestEngine`.
`byte[]`	`digest()`	Finalize the current hash computation and return the hash value in a newly-allocated array.
`byte[]`	`digest(byte[] input)`	Input some bytes, then finalize the current hash computation and return the hash value in a newly-allocated array.
`int`	`digest(byte[] buf, int offset, int len)`	Finalize the current hash computation and store the hash value in the provided output buffer.
`protected abstract void`	`doInit()`	This function is called at object creation time; the implementation should use it to perform initialization tasks.
`protected abstract void`	`doPadding(byte[] buf, int off)`	Perform the final padding and store the result in the provided buffer.
`protected abstract void`	`engineReset()`	Reset the hash algorithm state.
`protected int`	`flush()`	Flush internal buffers, so that less than a block of data may at most be upheld.
`protected byte[]`	`getBlockBuffer()`	Get a reference to an internal buffer with the same size than a block.
`protected long`	`getBlockCount()`	Get the "block count": this is the number of times the `processBlock(byte[])` method has been invoked for the current hash operation.
`protected int`	`getInternalBlockLength()`	Get the internal block length.
`protected abstract void`	`processBlock(byte[] data)`	Process one block of data.
`void`	`reset()`	Reset the object: this makes it suitable for a new hash computation.
`void`	`update(byte input)`	Insert one more input data byte.
`void`	`update(byte[] input)`	Insert some more bytes.
`void`	`update(byte[] input, int offset, int len)`	Insert some more bytes.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface fr.cryptohash.Digest

copy, getBlockLength, getDigestLength, toString

Constructor Details
- DigestEngine
  
  public DigestEngine()
  
  Instantiate the engine.
Method Details
- engineReset
  
  protected abstract void engineReset()
  
  Reset the hash algorithm state.
- processBlock
  
  protected abstract void processBlock(byte[] data)
  
  Process one block of data.
  
  Parameters:
  
  data - the data block
- doPadding
  
  protected abstract void doPadding(byte[] buf, int off)
  
  Perform the final padding and store the result in the provided buffer. This method shall call flush() and then update(byte) with the appropriate padding data in order to get the full input data.
  
  Parameters:
  
  buf - the output buffer
  
  off - the output offset
- doInit
  
  protected abstract void doInit()
  
  This function is called at object creation time; the implementation should use it to perform initialization tasks. After this method is called, the implementation should be ready to process data or meaningfully honour calls such as Digest.getDigestLength().
- digest
  
  public byte[] digest()
  
  Description copied from interface: Digest
  
  Finalize the current hash computation and return the hash value in a newly-allocated array. The object is resetted.
  
  Specified by:
  
  digest in interface Digest
  
  Returns:
  
  the hash output
  
  See Also:
  
  Digest
- digest
  
  public byte[] digest(byte[] input)
  
  Description copied from interface: Digest
  
  Input some bytes, then finalize the current hash computation and return the hash value in a newly-allocated array. The object is resetted.
  
  Specified by:
  
  digest in interface Digest
  
  Parameters:
  
  input - the input data
  
  Returns:
  
  the hash output
  
  See Also:
  
  Digest
- digest
  
  public int digest(byte[] buf, int offset, int len)
  
  Description copied from interface: Digest
  
  Finalize the current hash computation and store the hash value in the provided output buffer. The len parameter contains the maximum number of bytes that should be written; no more bytes than the natural hash function output length will be produced. If len is smaller than the natural hash output length, the hash output is truncated to its first len bytes. The object is resetted.
  
  Specified by:
  
  digest in interface Digest
  
  Parameters:
  
  buf - the output buffer
  
  offset - the output offset within outbuf
  
  len - the requested hash output length (in bytes)
  
  Returns:
  
  the number of bytes actually written in outbuf
  
  See Also:
  
  Digest
- reset
  
  public void reset()
  
  Description copied from interface: Digest
  
  Reset the object: this makes it suitable for a new hash computation. The current computation, if any, is discarded.
  
  Specified by:
  
  reset in interface Digest
  
  See Also:
  
  Digest
- update
  
  public void update(byte input)
  
  Description copied from interface: Digest
  
  Insert one more input data byte.
  
  Specified by:
  
  update in interface Digest
  
  Parameters:
  
  input - the input byte
  
  See Also:
  
  Digest
- update
  
  public void update(byte[] input)
  
  Description copied from interface: Digest
  
  Insert some more bytes.
  
  Specified by:
  
  update in interface Digest
  
  Parameters:
  
  input - the data bytes
  
  See Also:
  
  Digest
- update
  
  public void update(byte[] input, int offset, int len)
  
  Description copied from interface: Digest
  
  Insert some more bytes.
  
  Specified by:
  
  update in interface Digest
  
  Parameters:
  
  input - the data buffer
  
  offset - the data offset in inbuf
  
  len - the data length (in bytes)
  
  See Also:
  
  Digest
- getInternalBlockLength
  
  protected int getInternalBlockLength()
  
  Get the internal block length. This is the length (in bytes) of the array which will be passed as parameter to processBlock(byte[]). The default implementation of this method calls Digest.getBlockLength() and returns the same value. Overriding this method is useful when the advertised block length (which is used, for instance, by HMAC) is suboptimal with regards to internal buffering needs.
  
  Returns:
  
  the internal block length (in bytes)
- flush
  
  protected final int flush()
  
  Flush internal buffers, so that less than a block of data may at most be upheld.
  
  Returns:
  
  the number of bytes still unprocessed after the flush
- getBlockBuffer
  
  protected final byte[] getBlockBuffer()
  
  Get a reference to an internal buffer with the same size than a block. The contents of that buffer are defined only immediately after a call to flush(): if flush() return the value n, then the first n bytes of the array returned by this method are the n bytes of input data which are still unprocessed. The values of the remaining bytes are undefined and may be altered at will.
  
  Returns:
  
  a block-sized internal buffer
- getBlockCount
  
  protected long getBlockCount()
  
  Get the "block count": this is the number of times the processBlock(byte[]) method has been invoked for the current hash operation. That counter is incremented after the call to processBlock(byte[]).
  
  Returns:
  
  the block count
- copyState
  
  protected Digest copyState(DigestEngine dest)
  
  This function copies the internal buffering state to some other instance of a class extending DigestEngine. It returns a reference to the copy. This method is intended to be called by the implementation of the Digest.copy() method.
  
  Parameters:
  
  dest - the copy
  
  Returns:
  
  the value dest

Class DigestEngine

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface fr.cryptohash.Digest

Constructor Details

Method Details