mcrypt_cbc

Bubba at hines57 dot com (2012-07-22 04:59:51)

The PERL libraries have changed a little bit and getting PHP and PERL to mcrypt together can be confusing, so here is a current example;

PHP
===
<?php
$string = 'Some Secret thing I want to encrypt';
$iv = '12345678';
$passphrase = '8chrsLng';

$encryptedString = encryptString($string, $passphrase, $iv);
// Expect: 7DjnpOXG+FrUaOuc8x6vyrkk3atSiAf425ly5KpG7lOYgwouw2UATw== 

function encryptString($unencryptedText, $passphrase, $iv) {
  $enc = mcrypt_encrypt(MCRYPT_BLOWFISH, $passphrase, $unencryptedText, MCRYPT_MODE_CBC, $iv);
  return base64_encode($enc);
}
?>

PERL
====
$encryptedString = '7DjnpOXG+FrUaOuc8x6vyrkk3atSiAf425ly5KpG7lOYgwouw2UATw==';
$iv = '12345678';
$passphrase = '8chrsLng';

$string = &decryptPhpEncrypted $encryptedString, $passphrase, $iv;
# Expect: Some Secret thing I want to encrypt

sub decryptPhpEncrypted() {
  my ($encryptedString, $passphrase, $iv) = @_;
  my $keysize = length($passphrase);
  use Crypt::CBC;
  $cipher = Crypt::CBC->new( {'key' => $encryptedString,
                              'cipher'=> 'Blowfish',
                              'iv' => $iv,
                              'keysize' => $keysize,
                              'regenerate_key' => 0,
                              'padding' => 'null',
                              'prepend_iv' => 0});

  return $cipher->decrypt($encryptedString);
}

dafuk at dafuk dot co dot il (2012-04-25 11:20:08)

if you use blowfish and somehow when you compare strings before and after it was (usually when it's shorter than 8 or 16 bytes) you might notice the difference, it comes out that this function does not remove padding, as a result you get a bunch of nulls at the end.
use
$decrypted = rtrim($decrypted,"\0");
to fix it

Othman (2009-05-16 21:56:12)

The following code is to 
encrypt-->encode 
decode-->decrypt

<?php
$stuff="String to enc/enc/dec/dec =,=,";
$key="XiTo74dOO09N48YeUmuvbL0E";

function nl() {
    echo "<br/> \n";
}
$iv = mcrypt_create_iv (mcrypt_get_block_size (MCRYPT_TripleDES, MCRYPT_MODE_CBC), MCRYPT_DEV_RANDOM);

// Encrypting
function encrypt($string, $key) {
    $enc = "";
    global $iv;
    $enc=mcrypt_cbc (MCRYPT_TripleDES, $key, $string, MCRYPT_ENCRYPT, $iv);

  return base64_encode($enc);
}

// Decrypting 
function decrypt($string, $key) {
    $dec = "";
    $string = trim(base64_decode($string));
    global $iv;
    $dec = mcrypt_cbc (MCRYPT_TripleDES, $key, $string, MCRYPT_DECRYPT, $iv);
  return $dec;
}

$encrypted = encrypt($stuff, $key);
$decrypted = decrypt($encrypted, $key);

echo "Encrypted is ".$encrypted . nl(); 
echo "Decrypted is ".$decrypted . nl(); 
?>

Notes on the result 
-o running the script from the command line 1 time 
    php script.php works correct
-o if i ran the script in a loop i.e.

#!/bin/bash
for x in `seq 100` 
do
        echo $x
        php script.php >> LOG.text 
        sleep 1

done
it gets slower after the 10th time
+ inconsistent output 
sometimes correct some with encrypted characters at the end of the decrypted string 

-o Firefox on Linux it decrypts to the original string but appends 
    some encryption at the end of the decrypted sting
-o running the script on the browser from windows on Firefox, 
    Google Chrome, IE7 works fine for just few times 
    "refresh every few seconds" 
    if refresh fast it doesn't work correctly, 
    some times returns the decrypted as encrypted!
    some times returns mix of encrypted & decrypted

I thought if sharing that test for those functions might be 
useful for some body

(2006-04-28 08:44:38)

Here is a post similar to the one above, except this works for AES256
256 bit key and 128 bit block size... just make sure the $key variable is at least 48 characters long
---- PERL ---
my $key = '12345678901234567890123456789012345678901234567890';
my $CC = '4007000000027';
# You need Crypt::Rijndael installed for this to work
use Crypt::CBC;
my $cipher = Crypt::CBC->new( {'key' => substr($key,0,32),
'cipher'=> 'Rijndael',
'iv' => substr($key,32,16),
'regenerate_key' => 0,
'padding' => 'null',
'prepend_iv' => 0
});
my $encrypted = $cipher->encrypt($CC);
print "encrypted : ".$encrypted."\n";
print "decrypted : ".$cipher->decrypt($encrypted)."\n";
--- PHP ---
$key = '123456789012345678901234567890123456789012345678901234567890';
$CC = '4007000000027';
$encrypted = mcrypt_cbc(MCRYPT_RIJNDAEL_128,substr($key,0,32) ,$CC,MCRYPT_ENCRYPT,substr($key,32,16));
$decrypted = mcrypt_cbc(MCRYPT_RIJNDAEL_128,substr($key,0,32) ,$encrypted,MCRYPT_DECRYPT,substr($key,32,16));
echo "encrypted : ".bin2hex($encrypted);

eric at ez-llc dot com (2006-03-11 09:38:54)

I was able get php and perl to play together with blowfish using cipher block chaining. The blowfish key needs to be atleast 8 chars (even though blowfish min is 8 bits, perl didn't like keys smaller than 8 chars) and max 56. The iv must be exactly 8 chars and padding needs to be null because php pads with nulls. Also, php needs libmcrypt >= 2.4.9 to be compatible with perl.
PERL
----
use Crypt::CBC;
$cipher = Crypt::CBC->new( {'key' => 'my secret key',
'cipher'=> 'Blowfish',
'iv' => '12345678',
'regenerate_key' => 0,
'padding' => 'null',
'prepend_iv' => 0
});
$cc = 'my secret text';
$encrypted = $cipher->encrypt($cc);
$decrypted = $cipher->decrypt($encrypted);
print "encrypted : ".$encrypted;
print "<br>";
print "decrypted : ".$decrypted;
PHP
---
$cc = 'my secret text';
$encrypted = mcrypt_cbc(MCRYPT_BLOWFISH,'my secret key',$cc,MCRYPT_ENCRYPT,'12345678');
$decrypted = mcrypt_cbc(MCRYPT_BLOWFISH, 'my secret key', $encrypted, MCRYPT_DECRYPT,'12345678');
echo "encrypted : ".$encrypted;
echo "<br>";
echo "decrypted : ".$decrypted;