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rc4(n) 1.1.0 "RC4 Stream Cipher"

NAME

rc4 - Impementation of the RC4 stream cipher

    TABLE OF CONTENTS
    SYNOPSIS
    DESCRIPTION
    COMMANDS
    PROGRAMMING INTERFACE
    EXAMPLES
    AUTHORS
    SEE ALSO
    KEYWORDS
    COPYRIGHT

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

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]

rc4(n) 1.1.0 "RC4 Stream Cipher"

Copyright © 2006 for compilation: ActiveState