RSA Encryption in Perl

The Crypt::RC4 Module

Encrypting with the Module

There is a module on CPAN that should work on multiple platforms available at http://search.cpan.org/search?dist=Crypt-RC4. Using the Crypt::RC4 is also more convenient when we want to encrypt something from within a larger Perl program. For example, we may want to encrypt some Web form input, encrypt it, and send it in an email.

#!/usr/bin/perl -w
use strict;
use Crypt::RC4;
use Mail::Sendmail;
use CGI qw/:standard/;

my $key = '3353bc7';

my $name = param ('name');
my $ccnum = param('cc');
my $ccexp = param('ccexp');
my $message = "$name:$ccnum:$ccexp";

my $encrypted = RC4($key, $message);

sendmail((To      => 'eisen@xif.com',
	  From    => 'system@xif.com',
	  Subject => 'New Order',
	  Message => $encrypted,
	  smtp    => "my.mail.server")) 
    or die $Mail::Sendmail::error;

In the above example, we are pulling three variables from an HTML form, putting them into a colon delimited string, encrypting it, and then sending it out to a predefined recipient. The receiver, of course, won't be able to read the information without decrypting it first.

#!/usr/bin/perl -w
use strict;
use Crypt::RC4;

my $key = '1c07e37';
open (EMAIL,"email");
my $message = join('',<EMAIL>);
my $decrypted = RC4($key, $message);
open(FILE,">myfile") || die "$!\n";
print FILE $decrypted;
close(FILE);

The program above decrypts the body of the encrypted email and saves it to myfile. Nifty.