rc4(n)								 RC4 Stream Cipher							    rc4(n)

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NAME

       rc4 - Impementation of the RC4 stream cipher

SYNOPSIS

       package require Tcl  8.2

       package require rc4  ?1.1.0?

       ::rc4::rc4 ?-hex? -key keyvalue ?-command lst? ?-out channel? [ -in channel | -infile filename | string ]

       ::rc4::RC4Init keydata

       ::rc4::RC4 Key data

       ::rc4::RC4Final Key

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DESCRIPTION

       This  package is an implementation in Tcl of the RC4 stream cipher developed by Ron Rivest of RSA Data Security Inc. The cipher was a trade
       secret of RSA but was reverse-engineered and published to the internet in 1994. It is used in a number of network  protocols  for  securing
       communications. To evade trademark restrictions this cipher is sometimes known as ARCFOUR.

COMMANDS

       ::rc4::rc4 ?-hex? -key keyvalue ?-command lst? ?-out channel? [ -in channel | -infile filename | string ]
	      Perform  the  RC4 algorithm on either the data provided by the argument or on the data read from the -in channel. If an -out channel
	      is given then the result will be written to this channel.  Giving the -hex option will return a hexadecimal encoded version  of  the
	      result if not using an -out channel.

	      The  data to be processes can be specified either as a string argument to the rc4 command, or as a filename or a pre-opened channel.
	      If the -infile argument is given then the file is opened, the data read and processed and the file is closed. If the -in argument is
	      given  then  data  is read from the channel until the end of file. The channel is not closed. If the -out argument is given then the
	      processing result is written to this channel.

	      If -command is provided then the rc4 command does not return anything. Instead the command provided is called with  the  rc4  result
	      data  appended as the final parameter. This is most useful when reading from Tcl channels as a fileevent is setup on the channel and
	      the data processed in chunks

	      Only one of -infile, -in or string should be given.

PROGRAMMING INTERFACE

       ::rc4::RC4Init keydata
	      Initialize a new RC4 key. The keydata is any amount of binary data and is used to initialize the cipher internal state.

       ::rc4::RC4 Key data
	      Encrypt or decrypt the input data using the key obtained by calling RC4Init.

       ::rc4::RC4Final Key
	      This should be called to clean up resources associated with Key. Once this function has been called the key is destroyed.

EXAMPLES

       % set keydata [binary format H* 0123456789abcdef]
       % rc4::rc4 -hex -key $keydata HelloWorld
       3cf1ae8b7f1c670b612f
       % rc4::rc4 -hex -key $keydata [binary format H* 3cf1ae8b7f1c670b612f]
       HelloWorld

	set Key [rc4::RC4Init "key data"]
	append ciphertext [rc4::RC4 $Key $plaintext]
	append ciphertext [rc4::RC4 $Key $additional_plaintext]
	rc4::RC4Final $Key

	proc ::Finish {myState data} {
	    DoStuffWith $myState $data
	}
	rc4::rc4 -in $socket -command [list ::Finish $ApplicationState]

AUTHORS

       Pat Thoyts

BUGS, IDEAS, FEEDBACK
       This document, and the package it describes, will undoubtedly contain bugs and other problems.  Please report such in the category  rc4	of
       the  Tcllib  SF	Trackers [http://sourceforge.net/tracker/?group_id=12883].  Please also report any ideas for enhancements you may have for
       either package and/or documentation.

SEE ALSO

       aes(n), blowfish(n), des(n)

KEYWORDS

       arcfour,, data integrity, encryption, rc4, security, stream cipher

COPYRIGHT

       Copyright (c) 2003, Pat Thoyts <patthoyts@users.sourceforge.net>

rc4								       1.1.0								    rc4(n)