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Class cryptix.provider.cipher.RC4

java.lang.Object
   |
   +----java.security.IJCE_Traceable
           |
           +----java.security.Cipher
                   |
                   +----cryptix.provider.cipher.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: 1.3 $

Author:
Raif S. Naffah, David Hopwood

Constructor Index

 o RC4()
Constructs an RC4 cipher object, in the UNINITIALIZED state.

Method Index

 o clone()
Always throws a CloneNotSupportedException (cloning of ciphers is not supported for security reasons).
 o engineBlockSize()
SPI: Returns the length of an input block, in bytes.
 o engineInitDecrypt(Key)
SPI: Initializes this cipher for decryption, using the specified key.
 o engineInitEncrypt(Key)
SPI: Initializes this cipher for encryption, using the specified key.
 o engineUpdate(byte[], int, int, byte[], int)
SPI: This is the main engine method for updating data.
 o finalize()
Cleans up resources used by this instance, if necessary.
 o getLinkStatus()

Constructors

 o 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".

Methods

 o getLinkStatus
 public static LinkStatus getLinkStatus()
 o finalize
 protected final void finalize()
Cleans up resources used by this instance, if necessary.

Overrides:
finalize in class Object
 o clone
 public final Object clone() throws CloneNotSupportedException
Always throws a CloneNotSupportedException (cloning of ciphers is not supported for security reasons).

Overrides:
clone in class Cipher
 o 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.
Overrides:
engineBlockSize in class Cipher
 o engineInitEncrypt
 public void engineInitEncrypt(Key key) throws InvalidKeyException
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.
Overrides:
engineInitEncrypt in class Cipher
 o engineInitDecrypt
 public void engineInitDecrypt(Key key) throws InvalidKeyException
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.
Overrides:
engineInitDecrypt in class Cipher
 o 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.
Overrides:
engineUpdate in class Cipher

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