Using $this when not in object context

I installed and try using but I received an error message. 
**Fatal error:** Using $this when not in object context in **C:\xampp\htdocs\projectfolder\vendor\phpsec\phpsec\lib\phpSec\Crypt\Hash.php** on line **98**

content of index.php

``` php
<?php
//phpSec test
require 'vendor/autoload.php';

$hash = \phpSec\Crypt\Hash::create('password');
echo $hash;
```
