cryptix.provider.cipher

Class RC4

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

Constructor Summary
RC4()
Constructs an RC4 cipher object, in the UNINITIALIZED state.
Method Summary
Objectclone()
Always throws a CloneNotSupportedException (cloning of ciphers is not supported for security reasons).
intengineBlockSize()
SPI: Returns the length of an input block, in bytes.
voidengineInitDecrypt(Key key)
SPI: Initializes this cipher for decryption, using the specified key.
voidengineInitEncrypt(Key key)
SPI: Initializes this cipher for encryption, using the specified key.
protected intengineUpdate(byte[] in, int inOffset, int inLen, byte[] out, int outOffset)
SPI: This is the main engine method for updating data.
protected voidfinalize()
Cleans up resources used by this instance, if necessary.
static LinkStatusgetLinkStatus()

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

clone

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

engineBlockSize

public int engineBlockSize()
SPI: Returns the length of an input block, in bytes.

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

engineInitDecrypt

public void engineInitDecrypt(Key key)
SPI: Initializes this cipher for decryption, using the specified key.

Parameters: key the key to use for decryption.

Throws: InvalidKeyException if the key is invalid.

engineInitEncrypt

public void engineInitEncrypt(Key key)
SPI: Initializes this cipher for encryption, using the specified key.

Parameters: key the key to use for encryption.

Throws: 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.

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.

finalize

protected final void finalize()
Cleans up resources used by this instance, if necessary.

getLinkStatus

public static LinkStatus getLinkStatus()