Sd Card + Security

Is it possible for me to set up a system where by some files are encrypted unless a USB or SD card is present in the laptop?

Galen

You could use Truecrypt - it is available for all platforms.

I'd be interested in something that requires a key, present on some external media?

Khannie

Truecrypt fits that bill. While you can't force the key to be stored on an external drive, only keeping it on that drive would be your job. Otherwise you're looking at something custom that uses a dongle because linux wont differentiate between local and external storage (it's just a block device).

Orion

Another vote for Truecrypt. You can have the crypt on the external drive. For added security it also supports hidden volumes which are hidden crypts within crypts.

Hidden volumes don't work in Linux though...

I ask as the material I expect to be dealing with is legal documents that I don't really want floating around the place, and it would be pretty cool if the laptop needed an external 'key' to allow the files to be opened.

Ie, a truecrypt file (I use this program at the moment) requiring an exteranl key + password which holds another truecrypt folder containing the files.
Or is this overkill?

Khannie

Probably overkill. A crypt with a strong key and / or externally stored key should be enough to put off more or less everyone.