AES256 CBC Encryption with PKCS7 Padding in PHP

aes.php

<?php
function aes256_cbc($data, $key, $iv) 
{
    // padding
    $blocksize = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128,'cbc');
    $len = strlen($data);
    $pad = $blocksize - ($len % $blocksize);
    $data .= str_repeat(chr($pad), $pad);
    // encrypting & encoding
    return base64_encode( mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv) ) ;
}


?>