FPGA Bitstream Security Broken 90
NumberField writes "Researchers in Germany released a pair of papers documenting severe power analysis vulnerabilities in the bitstream encryption of multiple Xilinx FPGAs. The problem exposes products using FPGAs to cloning, hardware Trojan insertion, and reverse engineering. Unfortunately, there is no easy downloadable fix, as hardware changes are required. These papers are also a reminder that differential power analysis (DPA) remains a potent threat to unprotected hardware devices. On the FPGA front, only Actel seems to be tackling the DPA issue so far, although their FPGAs are much smaller than Xilinx's."
Re:they would have to add additional circuitry... (Score:4, Insightful)
There is only so much you can do. We put a fair amount of power supply filtering around FPGAs because of the switching noise, but the cost in board space and materials to make the switching undetectable would be astronomical. As HW engineers we're always asked to cram a little more in that space, and "do you really need that many capacitors?"
The company I work for (and the reason I'm posting anonymously) uses a bunch of FPGAs per board with man-years of code invested into them, and we usually use Xilinx parts. It's relatively trivial to get the bitstreams from our systems which hasn't bothered us since they're encrypted (or I guess they used to be).
Re:Good or bad? (Score:4, Insightful)
Also, if you SELL products with FPGAs in them, it makes it harder to make a profit if somebody decides to reverse-engineer your stuff. Really, all this is good for is cracking into a design that somebody else made. Once you GET the actual bitstream, there are really two things that you can do with it...
1) Make copies of the FPGA. Boards are not that hard to reverse-engineer, so you could copy somebody else's design completely.
2) Reverse engineer the code. However, you will NOT have anything that would help you do this, like net names or hierarchies. This will make actual reverse-engineering in order to change something or learn something very challenging.
This doe NOT make FPGAs any more useful, since you can easily download free development software from every FPGA vendor and put whatever you want on there. Really, the only thing that you CAN'T do with the free software is stuff related to licensed IP (processor cores, various controllers for things like Ethernet, SATA, etc.). While you COULD pull that out of an encrypted bitstream, using it without any sort of documentation or the configuration wizards would be very challenging and, 9 times out of 10, it is just easier to pony up the money to license the cores in the first place.
Re:DPA protection is patented... (Score:5, Insightful)
Yet another idiot who doesn't understand the simple fact that the 'obvious' test is applied BEFORE the patent is public. Of course it is 'obvious' AFTER the patent is public. If you asked 100 people working in the field how to "defend against DPA and other side-channel attacks" BEFORE the patent (or anything using the patent, or any papers based on the patent, etc) was public, what percentage of them would have come up with the EXACT SAME WAY (not 'general concepts', the exact methods used) that CR did? It had better be very close to 100% if you are going to claim 'obvious'. If you ask these same 100 people AFTER the patent is public, 99 of them will claim that the CR method is 'obvious'.