Just got Ubuntu 14.04 running on a Zotac Zbox CI320. I want to enable the Samsung 840 hard ware encryption that comes with this hard drive, but I don't know how.
Is there anyone that can help me set this up? Much appreciated.
There are different kinds of hardware encryption on SSDs, see SSDs with usable built-in hardware-based full disk encryption for an in-depth explanation.
You asked about the Samsung 840 EVO in particular. It is always encrypting your data and is unlocked by the ATA HDD password set in the BIOS, which defaults to blank. Later you can move the SSD to a new machine and enter the the ATA HDD password via the BIOS there to unlock it. Nothing involved in unlocking is stored outside of the drive itself.
As a Linux user, I prefer this solution over software-based drive encryption. There is no performance penalty and it is simple to setup and use.
I found the following similar questions:
While an answer in one of the questions above offers a solution that might even work in your case you should consider the following:
Edit: Michael Larabel posted articles on Phoronix where he speculates that SED/OPAL support may be coming to Linux soon, just in case anyone stumbles over this post from the past looking for more up to date information.