'\"
'\" Generated from file 'rc4\&.man' by tcllib/doctools with format 'nroff'
'\" Copyright (c) 2003, Pat Thoyts <patthoyts@users\&.sourceforge\&.net>
'\"
.TH "rc4" n 1\&.2\&.0 tcllib "RC4 Stream Cipher"
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.SH NAME
rc4 \- Implementation of the RC4 stream cipher
.SH SYNOPSIS
package require \fBTcl 8\&.5 9\fR
.sp
package require \fBrc4 ?1\&.2\&.0?\fR
.sp
\fB::rc4::rc4\fR ?\fI-hex\fR? \fI-key keyvalue\fR ?\fI-command lst\fR? ?\fI-out channel\fR? [ \fI-in channel\fR | \fI-infile filename\fR | \fIstring\fR ]
.sp
\fB::rc4::RC4Init\fR \fIkeydata\fR
.sp
\fB::rc4::RC4\fR \fIKey\fR \fIdata\fR
.sp
\fB::rc4::RC4Final\fR \fIKey\fR
.sp
.BE
.SH DESCRIPTION
.PP
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\&.
.SH COMMANDS
.TP
\fB::rc4::rc4\fR ?\fI-hex\fR? \fI-key keyvalue\fR ?\fI-command lst\fR? ?\fI-out channel\fR? [ \fI-in channel\fR | \fI-infile filename\fR | \fIstring\fR ]
Perform the RC4 algorithm on either the data provided by the argument
or on the data read from the \fI-in\fR channel\&. If an \fI-out\fR
channel is given then the result will be written to this channel\&.
Giving the \fI-hex\fR option will return a hexadecimal encoded
version of the result if not using an \fI-out\fR channel\&.
.sp
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
\fI-infile\fR argument is given then the file is opened, the data read
and processed and the file is closed\&. If the \fI-in\fR argument is
given then data is read from the channel until the end of file\&. The
channel is not closed\&. If the \fI-out\fR argument is given then the
processing result is written to this channel\&.
.sp
If \fI-command\fR 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
.sp
Only one of \fI-infile\fR, \fI-in\fR or \fIstring\fR should be given\&.
.PP
.SH "PROGRAMMING INTERFACE"
.TP
\fB::rc4::RC4Init\fR \fIkeydata\fR
Initialize a new RC4 key\&. The \fIkeydata\fR is any amount of binary
data and is used to initialize the cipher internal state\&.
.TP
\fB::rc4::RC4\fR \fIKey\fR \fIdata\fR
Encrypt or decrypt the input data using the key obtained by calling
\fBRC4Init\fR\&.
.TP
\fB::rc4::RC4Final\fR \fIKey\fR
This should be called to clean up resources associated with
\fIKey\fR\&. Once this function has been called the key is destroyed\&.
.PP
.SH EXAMPLES
.CS


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

.CE
.CS


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

.CE
.CS


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

.CE
.SH AUTHORS
Pat Thoyts
.SH "BUGS, IDEAS, FEEDBACK"
This document, and the package it describes, will undoubtedly contain
bugs and other problems\&.
Please report such in the category \fIrc4\fR of the
\fITcllib Trackers\fR [http://core\&.tcl\&.tk/tcllib/reportlist]\&.
Please also report any ideas for enhancements you may have for either
package and/or documentation\&.
.PP
When proposing code changes, please provide \fIunified diffs\fR,
i\&.e the output of \fBdiff -u\fR\&.
.PP
Note further that \fIattachments\fR are strongly preferred over
inlined patches\&. Attachments can be made by going to the \fBEdit\fR
form of the ticket immediately after its creation, and then using the
left-most button in the secondary navigation bar\&.
.SH "SEE ALSO"
aes(n), blowfish(n), des(n)
.SH KEYWORDS
arcfour, data integrity, encryption, rc4, security, stream cipher
.SH CATEGORY
Hashes, checksums, and encryption
.SH COPYRIGHT
.nf
Copyright (c) 2003, Pat Thoyts <patthoyts@users\&.sourceforge\&.net>

.fi
