I think this is a slight update of http://news.ycombinator.com/item?id=4035748 where a lot of the obvious questions (JTAG? Over the Internet? Is it a maliious backdoor or engineering/debugging leftovers?...) have already been discussed.
Scientist prepares paper for CHES conference - with a little over-the-top wording in the _draft_. Paper is leaked to the internet and blown out of proportion.
It's still interesting reading. Maybe Microsemi will finally listen to these guys and stop using the same password for the backdoor in _all_ of the following chips: "all ProASIC3, Igloo, Fusion and SmartFusion FPGAs" [1]
Ok and PEA is just their patented method of automating differential power analysis using a test jig - it does the repetitive process using a microcontroller and some sensors instead of doing it after sampling everything with an o-scope. It's a good idea and they have worked out the fiddly little details... but a pretty simple concept.
Okay, but if I am reading correctly, the original post talks about access over the internet due to designed remote upgrade abilities while the URL provided for the entrust.com article says physical access is required.
This parent post looks like a much more thorough threat to me, depending on where the chips are used...
One very noteworthy thing from the article: They claim to be able to read back configuration from a otherwise erased device by changing the reference voltage of the read-sense amplifiers "used by the backdoor" (=the undocumented command that allows reading back the supposedly write-only configuration data). (pg15, top paragraph)
It's not a backdoor, just uncontrolled engineering. I bet you that the product manager never knew about this; it's provably a capability buried deep inside the ip block (which, logically, is used in other Actel parts).
Low cost ICs are incredibly complex nowadays, to the point defending even the most integrated, self-contained of parts is near impossible. I've been doing security analysis for manufacturers of high end microcontrollers and these parts are packed with features to the point they are just hard to seal.
It's common to have a debugging/manufacturing/update/boot mechanism that can be used for attacks even when things are supposedly locked down.