mcrypt_cbc

(PHP 4, PHP 5)

mcrypt_cbc — Encrypt/decrypt data in CBC mode

Description

string mcrypt_cbc ( int $cipher , string $key , string $data , int $mode [, string $iv ] )
string mcrypt_cbc ( string $cipher , string $key , string $data , int $mode [, string $iv ] )

The first prototype is when linked against libmcrypt 2.2.x, the second when linked against libmcrypt 2.4.x or higher. The mode should be either MCRYPT_ENCRYPT or MCRYPT_DECRYPT.

This function should not be used anymore, see mcrypt_generic() and mdecrypt_generic() for replacements.

Коментарии

Автор:
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_TripleDESMCRYPT_MODE_CBC), MCRYPT_DEV_RANDOM);

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

  return 
base64_encode($enc);
}

// Decrypting 
function decrypt($string$key) {
   
$dec "";
   
$string trim(base64_decode($string));
    global 
$iv;
   
$dec mcrypt_cbc (MCRYPT_TripleDES$key$stringMCRYPT_DECRYPT$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
2009-05-17 00:56:12
http://php5.kiev.ua/manual/ru/function.mcrypt-cbc.html
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
2012-04-25 14:20:08
http://php5.kiev.ua/manual/ru/function.mcrypt-cbc.html
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$unencryptedTextMCRYPT_MODE_CBC$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);
}
2012-07-22 07:59:51
http://php5.kiev.ua/manual/ru/function.mcrypt-cbc.html

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