I had to drill it open. There's a video of the process here: http://www.wired.com/threatlevel/2011/05/gps-video/

Re: software—we linked to the reference design, which includes a lot of information about the software. There should be plenty of information available to start investigating their implementation.

Potting is still used heavily in industrial electronics and a lot of appliance work (think of washing machine control boards). I would think the military uses it a lot as well.

FIPS 140-2 Level 4 http://en.wikipedia.org/wiki/FIPS_140-2

Level 2-4 are used in commercial and military grade hardware security Modules.

I remember finding a teardown of an IBM 4765 module somewhere. That was badass.

Is that the PCIe crypto module shown in Google searches for IBM 4765? Please share the link if you have it, as I couldn't find a teardown in my brief search. I'd like to see how one would dismantle a potted circuit.

Yeah it's the crypto module. I think the teardown involved shaving the part down layer by layer and examining all the parts like the fine wire meshes that would instantly blow the chip if disrupted and etc. Wish I could remember where I saw it.