That was my thinking, yes. They could put in a very generic remote kill-switch, perhaps… fry the entire chip or reset it or something; but as they would have no idea ahead of time what sort of logic the user would put in there, there’s no way they could design a specific backdoor to anything.
The one exception might be if you use an FPGA for a network controller and the channels used to send data were predefined as part of the chip’s design, a generic backdoor could somehow exfiltrate that data via other means (same for wireless emissions – but TEMPEST-style techniques are now very well-known and defences can be erected outside of your local system).
That was my thinking, yes. They could put in a very generic remote kill-switch, perhaps… fry the entire chip or reset it or something; but as they would have no idea ahead of time what sort of logic the user would put in there, there’s no way they could design a specific backdoor to anything.
The one exception might be if you use an FPGA for a network controller and the channels used to send data were predefined as part of the chip’s design, a generic backdoor could somehow exfiltrate that data via other means (same for wireless emissions – but TEMPEST-style techniques are now very well-known and defences can be erected outside of your local system).