[Class] Criptografia SHA256 PHP

<?php

class Criptografia {

    private $chave = null, $iv = null;

    function __construct($senha) {
        $this->chave = hash('SHA256', $senha, TRUE);
        $this->iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_DEV_RANDOM);
    }

    function encrypt($input) {
        return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this->chave, $input, MCRYPT_MODE_ECB, $this->iv));
    }

    function decrypt($input) {
        return trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $this->chave, base64_decode($input), MCRYPT_MODE_ECB, $this->iv));
    }

}