AES encryption and decryption

Aes.php

<?php

class Aes
{

    private static $key = 'your_key';
    private static $iv  = 'your_iv';

    public static function encrypt($data)
    {
        return base64_encode(mcrypt_encrypt(
            MCRYPT_RIJNDAEL_128,
            self::$key,
            self::pkcs5_pad($data),
            MCRYPT_MODE_CBC,
            self::$iv
        ));
    }

    public static function decrypt($data)
    {
        $str = mcrypt_decrypt(
            MCRYPT_RIJNDAEL_128,
            self::$key,
            base64_decode($data),
            MCRYPT_MODE_CBC,
            self::$iv
        );
        return self::pkcs5_unpad($str);
    }

    private static function pkcs5_pad($text)
    {
        $blocksize = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
        $pad       = $blocksize - (strlen($text) % $blocksize);
        return $text . str_repeat(chr($pad), $pad);
    }

    private static function pkcs5_unpad($text)
    {
        $block = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
        $pad   = ord($text[($len = strlen($text)) - 1]);
        $len   = strlen($text);
        $pad   = ord($text[$len - 1]);
        return substr($text, 0, strlen($text) - $pad);
    }

}