class Sifrele{

    private $password   = "A472c47Ad52a";
    private $method     = "aes-256-cbc";
    private $iv;
    private $key;
    function __construct(){
        $this->iv = chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0) . chr(0x0);
    }

    function key(){
        return substr(hash('sha256', $this->password, true), 0, 32);
    }

    function encode($metin){
        return base64_encode(openssl_encrypt($metin, $this->method, $this->key, OPENSSL_RAW_DATA, $this->iv));
    }

    function decode($metin){
        return openssl_decrypt(base64_decode($metin), $this->method, $this->key, OPENSSL_RAW_DATA, $this->iv);
    }
}

$sifrele = new Sifrele();
$encode = $sifrele->encode('Şifrelenecek metini giriniz');
echo('Şifreli metin : ' . $encode . '<br>');
echo('Çözülmüş metin : ' . $sifrele->decode($encode) . '<br>');