2-Way Encryption Scheme

gistfile1.txt

class Encryption
{
    public function encrypt($plaintext,$key)
    { 
        $td = mcrypt_module_open(MCRYPT_RIJNDAEL_256, '', MCRYPT_MODE_CBC, '');
        $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
        mcrypt_generic_init($td, $key, $iv);
        $crypttext = mcrypt_generic($td, $plaintext);
        mcrypt_generic_deinit($td);
        return base64_encode($iv.$crypttext);
    }

    public function decrypt($crypttext, $key)
    {
        $crypttext = base64_decode($crypttext);
        $plaintext = '';
        $td        = mcrypt_module_open(MCRYPT_RIJNDAEL_256, '', MCRYPT_MODE_CBC, '');
        $ivsize    = mcrypt_enc_get_iv_size($td);
        $iv        = substr($crypttext, 0, $ivsize);
        $crypttext = substr($crypttext, $ivsize);
        if ($iv)
        {
            mcrypt_generic_init($td, $key, $iv);
            $plaintext = mdecrypt_generic($td, $crypttext);
        }
        return $plaintext;
    }
}