rc4(n)                         RC4 Stream Cipher                        rc4(n)



______________________________________________________________________________

NAME
       rc4 - Implementation 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

_________________________________________________________________

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

CATEGORY
       Hashes, checksums, and encryption

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




rc4                                  1.1.0                              rc4(n)
