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.\" ========================================================================
.\"
.IX Title "Tea 3"
.TH Tea 3 "2002-09-16" "perl v5.8.0" "User Contributed Perl Documentation"
.SH "NAME"
Tea.pm \- The Tiny Encryption Algorithm in Perl and JavaScript
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
Usage:
.PP
.Vb 7
\&        use Crypt::Tea;
\&        $key = 'PUFgob$*LKDF D)(F IDD&P?/';
\&        $ascii_ciphertext = &encrypt ($plaintext, $key);
\&        ...
\&        $plaintext_again = &decrypt ($ascii_ciphertext, $key);
\&        ...
\&        $signature = &asciidigest ($text);
.Ve
.PP
In \s-1CGI\s0 scripts:
.PP
.Vb 3
\&        use Crypt::Tea;
\&        print &tea_in_javascript;  # now the browser can encrypt
\&        # and decrypt ! see CGI::Htauth.pm for examples ...
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This module implements \s-1TEA\s0, the Tiny Encryption Algorithm,
and some Modes of Use, in Perl and JavaScript.
.PP
The \f(CW$key\fR is a sufficiently longish string; at least 17 random 8\-bit
bytes for single encryption.
.PP
As of version 1.34, various Htauth-specific hook routines
have now been moved out into the \fICGI::Htauth.pm\fR module.
.PP
Version 1.43,
#COMMENT#
.PP
(c) Peter J Billam 1998
.SH "SUBROUTINES"
.IX Header "SUBROUTINES"
.ie n .IP "\fIencrypt\fR( $plaintext\fR, \f(CW$key );" 3
.el .IP "\fIencrypt\fR( \f(CW$plaintext\fR, \f(CW$key\fR );" 3
.IX Item "encrypt( $plaintext, $key );"
Encrypts with \s-1CBC\s0 (Cipher Block Chaining)
.ie n .IP "\fIdecrypt\fR( $ciphertext\fR, \f(CW$key );" 3
.el .IP "\fIdecrypt\fR( \f(CW$ciphertext\fR, \f(CW$key\fR );" 3
.IX Item "decrypt( $ciphertext, $key );"
Decrypts with \s-1CBC\s0 (Cipher Block Chaining)
.ie n .IP "\fIbinary2ascii\fR( $a_binary_string );" 3
.el .IP "\fIbinary2ascii\fR( \f(CW$a_binary_string\fR );" 3
.IX Item "binary2ascii( $a_binary_string );"
Provide an ascii text encoding of the binary argument.
If Tea.pm is not being invoked from a \s-1GCI\s0 script,
the ascii is split into lines of 72 characters.
.ie n .IP "\fIascii2binary\fR( $an_ascii_string );" 3
.el .IP "\fIascii2binary\fR( \f(CW$an_ascii_string\fR );" 3
.IX Item "ascii2binary( $an_ascii_string );"
.PD 0
.ie n .IP "\fIasciidigest\fR( $a_string );" 3
.el .IP "\fIasciidigest\fR( \f(CW$a_string\fR );" 3
.IX Item "asciidigest( $a_string );"
.PD
Returns an asciified binary signature of the argument.
.IP "\fItea_in_javascript\fR();" 3
.IX Item "tea_in_javascript();"
Returns a compatible implementation of \s-1TEA\s0 in JavaScript,
for use in \s-1CGI\s0 scripts to communicate with browsers.
.SH "AUTHOR"
.IX Header "AUTHOR"
Peter J Billam <peter@pjb.com.au>,
with thanks also to Neil Watkiss for MakeMaker packaging.
.SH "CREDITS"
.IX Header "CREDITS"
Based on \s-1TEA\s0, as described in
http://www.cl.cam.ac.uk/ftp/papers/djw\-rmn/djw\-rmn\-tea.html ,
and on some help from \fIApplied Cryptography\fR by Bruce Schneier
as regards the modes of use.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
http://www.pjb.com.au/, CGI::Htauth.pm, \fIperl\fR\|(1).