I've not had much experience with modern allegedly "secure" FPGAs, but the scenario I see here is if your synthesis tools get compromised by a bad update (or an

I've not had much experience with modern allegedly "secure" FPGAs, but the scenario I see here is if your synthesis tools get compromised by a bad update (or another attack), they could add a little bit of "side logic" to every design. Solarwinds style. With encrypted output and what I understand to be no ability to carry out QA/evaluation on the bitstream (with encryption meaning binary comparisons shouldn't be meaningful), you can't really gain assurance that the output is as expected. Of course you could argue that you compare the encrypted bitstream with your "final version", but this only works until you need to use the field programmable aspect to update something, and now you have to take a leap of faith and flash the bitstream, and hope your build environment is good, as there's no real way to check.