cryptix.provider.cipher

Class RC4

java.lang.Object

xjava.security.IJCE_Traceable

xjava.security.Cipher

cryptix.provider.cipher.RC4

All Implemented Interfaces:

Parameterized, SymmetricCipher

public final class RC4
extends Cipher
implements SymmetricCipher

This class implements the RC4 (TM) stream cipher.

The source code (C version) from which this port was done, is the one posted to the sci.crypt, alt.security, comp.security.misc, and alt.privacy newsgroups on Wed, 14 Sep 1994 06:35:31 GMT by "David Sterndark" <sterndark@netcom.com> (Message-ID: <sternCvKL4B.Hyy@netcom.com>)

RC4 (TM) was designed by Ron Rivest, and was previously a trade secret of RSA Data Security, Inc. The algorithm is now in the public domain. The name "RC4" is a trademark of RSA Data Security, Inc.

References:

1. Bruce Schneier, "Section 17.1 RC4," Applied Cryptography, 2nd edition, John Wiley & Sons, 1996.

Copyright © 1997 Systemics Ltd on behalf of the Cryptix Development Team.
All rights reserved.

$Revision: 1.5 $

Since:

Cryptix 2.2.2

Author:

Raif S. Naffah, David Hopwood

Field Summary

Fields inherited from class xjava.security.Cipher

DECRYPT, ENCRYPT, UNINITIALIZED

Constructor Summary

Constructors

Constructor and Description
RC4() Constructs an RC4 cipher object, in the UNINITIALIZED state.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	clone() Always throws a CloneNotSupportedException (cloning of ciphers is not supported for security reasons).
int	engineBlockSize() SPI: Returns the length of an input block, in bytes.
void	engineInitDecrypt(java.security.Key key) SPI: Initializes this cipher for decryption, using the specified key.
void	engineInitEncrypt(java.security.Key key) SPI: Initializes this cipher for encryption, using the specified key.
protected int	engineUpdate(byte[] in, int inOffset, int inLen, byte[] out, int outOffset) SPI: This is the main engine method for updating data.
protected void	finalize() Cleans up resources used by this instance, if necessary.
static LinkStatus	getLinkStatus()

Methods inherited from class xjava.security.Cipher

blockSize, crypt, crypt, crypt, doFinal, doFinal, doFinal, doFinal, engineCiphertextBlockSize, engineCrypt, engineGetParameter, engineInBufferSize, engineOutBufferSize, enginePlaintextBlockSize, engineSetPaddingScheme, engineSetParameter, getAlgorithm, getAlgorithms, getAlgorithms, getCiphertextBlockSize, getInputBlockSize, getInstance, getInstance, getInstance, getMode, getOutputBlockSize, getPadding, getPaddingScheme, getParameter, getPlaintextBlockSize, getProvider, getState, inBufferSize, inBufferSizeFinal, initDecrypt, initEncrypt, isPaddingBlockCipher, outBufferSize, outBufferSizeFinal, setParameter, toString, update, update, update, update

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

RC4

public RC4()

Constructs an RC4 cipher object, in the UNINITIALIZED state. This calls the Cipher constructor with implBuffering false, implPadding false and the provider set to "Cryptix".

Method Detail

getLinkStatus

public static LinkStatus getLinkStatus()

finalize

protected final void finalize()

Cleans up resources used by this instance, if necessary.

Overrides:

finalize in class java.lang.Object

clone

public final java.lang.Object clone()
                             throws java.lang.CloneNotSupportedException

Always throws a CloneNotSupportedException (cloning of ciphers is not supported for security reasons).

Overrides:

clone in class Cipher

Throws:

java.lang.CloneNotSupportedException - if the cipher is not cloneable.

engineBlockSize

public int engineBlockSize()

SPI: Returns the length of an input block, in bytes.

Overrides:

engineBlockSize in class Cipher

Returns:

the length in bytes of an input block for this cipher.

engineInitEncrypt

public void engineInitEncrypt(java.security.Key key)
                       throws java.security.InvalidKeyException

SPI: Initializes this cipher for encryption, using the specified key.

Specified by:

engineInitEncrypt in class Cipher

Parameters:

key - the key to use for encryption.

Throws:

java.security.InvalidKeyException - if the key is invalid.

engineInitDecrypt

public void engineInitDecrypt(java.security.Key key)
                       throws java.security.InvalidKeyException

SPI: Initializes this cipher for decryption, using the specified key.

Specified by:

engineInitDecrypt in class Cipher

Parameters:

key - the key to use for decryption.

Throws:

java.security.InvalidKeyException - if the key is invalid.

engineUpdate

protected int engineUpdate(byte[] in,
                           int inOffset,
                           int inLen,
                           byte[] out,
                           int outOffset)

SPI: This is the main engine method for updating data.

in and out may be the same array, and the input and output regions may overlap.

Specified by:

engineUpdate in class Cipher

Parameters:

in - the input data.

inOffset - the offset into in specifying where the data starts.

inLen - the length of the subarray.

out - the output array.

outOffset - the offset indicating where to start writing into the out array.

Returns:

the number of bytes written.

Throws:

CryptixException - if the native library is being used, and it reports an error.