Making Perl Crypt::CBC work with PHP mcrypt_cbc()

[josh.kuo@gmail.com]

First of all, I know this is a PHP news group, so my question may not
be completely appropriate here since it involves some perl.

I have read this post that dealt with a similar problem that I am
having now:
http://groups.google.com/group/comp....se_thread/thre...

Summary of my problem:
I need to have a perl script that encrypts a string, write the output
to a file,
and then have a PHP script read the file, and decrypts it. I took most
of the code from this URL:

http://us2.php.net/manual/en/function.mcrypt-cbc.php

Below is my perl code used to encrypt

<perl>
#!/usr/bin/perl
use MIME::Base64;
use Crypt::CBC;
my $key = '01234567890123 456789012345678 9';
my $iv = '12345678';
my $text = 'This is my plain text';
$cipher = Crypt::CBC->new({'literal_ key' => 0,
'key' => $key,
'cipher' => 'Blowfish',
'iv' => $iv,
'padding' => 'null',
'prepend_iv' => 0});
$encrypted = $cipher->encrypt($text) ;
$encoded = encode_base64($ encrypted);
open(FILE, ">encrypt.txt") ;
print FILE $encoded;
close(FILE);
</perl>

And here's my PHP script used to decrypt:

<?php
$key = '01234567890123 456789012345678 9';
$iv = '12345678';
$lines = file('encrypt.t xt');
$encoded = '';
foreach ($lines as $line) {
$encoded .= $line;
}

$encrypted = base64_decode($ encoded);
$decrypted = mcrypt_cbc(MCRY PT_BLOWFISH, $key, $bin_encrypted,
MCRYPT_DECRYPT, $iv);
echo "decrypted : [$decrypted]";
exit();
?>

But the decryption doesn't seem to work... If I printed out the base64
encoded strings, they match. So I suspect it's something that I did
not do correctly either in the encryption or decryption of the message.

Any help is appreciated.

[josh.kuo@gmail.com]

Re: Making Perl Crypt::CBC work with PHP mcrypt_cbc()

Answer my own question...

The perl Crypt::CBC documentation states that the '-regenerate_key' and
'-prepent_iv' are deprecated, that's why I used '-literal_key' instead
of '-regenerate_key' .

However, when I switch back to use the old '-regenerate_key' , I got a
different error:

If specified by -literal_key, then the key length must be equal to the
chosen cipher's key length of 56 bytes at ./blow.pl line 9

So I changed my key to something like this in both perl and PHP:

my $long_key = "01234567890123 456789012345678 901234567890123 456789"
my $key = substr($long_ke y, 0, 56);

And while decrypting on the PHP end, I needed to use rtrim() on the
decrypted string.

After these changes everything is working.