I've installed Kali Linux as the only OS(which it will remain) on a 100GB partition on the hard drive in my laptop. I didn't set up the encryption while installing it and I would now like for it to be fully encrypted. I was able to encrypt a previous hard drive that had Windows 7 on it, very easily, but it appears as if I no longer have the same options within Kali Linux.

Is it possible to encrypt my hard drive at this point, or will I have to reinstall Kali Linux, and if it is possible, can you explain how to?