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[comment {-*- tcl -*- doctools manpage}]
[manpage_begin rc4 n 1.0.1]
[copyright {2003, Pat Thoyts <patthoyts@users.sourceforge.net>}]
[moddesc {RC4 Stream Cipher}]
[titledesc {Impementation of the RC4 stream cipher}]
[require Tcl 8.2]
[require rc4 [opt 1.0.1]]
[description]
[para]
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.
[section {COMMANDS}]
[list_begin definitions]
[call [cmd "::rc4::rc4"] \
[opt "[arg -hex]"] \
[arg "-key keyvalue" ] \
[opt [arg "-out channel"]] \
[lb] [arg "-in channel"] | \
[arg "-infile filename"] | [arg "string"] [rb]]
Perform the RC4 algorithm on either the data provided by the argument
or on the data read from the [arg "-in"] channel. If an [arg "-out"]
channel is given then the result will be written to this channel.
Giving the [arg "-hex"] option will return a hexadecimal encoded
version of the result if not using an [arg -out] channel.
[nl]
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
[arg "-infile"] argument is given then the file is opened, the data read
and processed and the file is closed. If the [arg "-in"] argument is
given then data is read from the channel until the end of file. The
channel is not closed. If the [arg "-out"] argument is given then the
processing result is written to this channel.
[nl]
Only one of [arg "-infile"], [arg "-in"] or [arg "string"] should be given.
[list_end]
[section "PROGRAMMING INTERFACE"]
[list_begin definitions]
[call [cmd "::rc4::RC4Init"] [arg "keydata"]]
Initialize a new RC4 key. The [arg keydata] is any amount of binary
data and is used to initialize the cipher internal state.
[call [cmd "::rc4::RC4"] [arg "Key"] [arg "data"]]
Encrypt or decrypt the input data using the key obtained by calling
[cmd RC4Init].
[call [cmd "::rc4::RC4Final"] [arg "Key"]]
This should be called to clean up resources associated with
[arg Key]. Once this function has been called the key is destroyed.
[list_end]
[section "EXAMPLES"]
[example {
% set keydata [binary format H* 0123456789abcdef]
% rc4::rc4 -hex -key $keydata HelloWorld
3cf1ae8b7f1c670b612f
% rc4::rc4 -hex -key $keydata [binary format H* 3cf1ae8b7f1c670b612f]
HelloWorld
}]
[example {
set Key [rc4::RC4Init "key data"]
append ciphertext [rc4::RC4 $Key $plaintext]
append ciphertext [rc4::RC4 $Key $additional_plaintext]
rc4::RC4Final $Key
}]
[see_also des(n) aes(n) blowfish(n)]
[section "AUTHORS"]
Pat Thoyts
[keywords rc4 arcfour, {stream cipher} security encryption {data integrity}]
[manpage_end]
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