Question: I have a login and sign up form and use the encrypt library to encrypt the password.. I am using Xampp for my server and my system works correctly..

code to encrypt the password:

```
$this->encrypt->encode('my password'); 

```

add encrypt library 

```
 $autoload['libraries'] = array('encrypt');

```

and setting the secret key in config:

```
$config['encryption_key'] = 'nmsc encrypt secret key';

```

My code works well using xampp server in windows but when Im trying to upload my website to ubuntu server I've got an error says 

> 
> The Encrypt library requires the Mcrypt extension
> 
> 
> 

how to fix that problem? refering this guide <https://www.codeigniter.com/user_guide/libraries/encryption.html> but I dont know how to install that mcrypt. my website needs to run from ubuntu server. how to install or fix that problem?

Answer: 
Best solution is (only available for CI 3 and up):

change 

```
 $this->load->library('encrypt');

```

to 

```
 $this->load->library('encryption');

```
You should install the PHP mcrypt module;

```
sudo apt-get install php5-mcrypt
sudo php5enmod mcrypt

```

And normally you will be good ;)