6 ms·

What can you trust then? License an ARM or MIPS IP core (in HDL form so it can be audited) and run it in an FPGA (or if you're rich, an ASIC)?

crest 13y ago
Some FPGAs are known to have backdoors (if you have JTAG access).
- ChuckMcM 13y ago
  That is more like front door access but still.
kryptiskt 13y ago
> and run it in an FPGA (or if you're rich, an ASIC)? An FPGA contains way more junk than just the gate array these days. And I don't know why you would trust Xilinx or Altera (who are way more dependent on government orders than Intel) over Intel. Or any fab, for that matter. I think it's reasonable to be paranoid, but at some point one should do a cost-benefit analysis of the measures one is willing to indulge in. Because ultimately you will have to trust someone blindly, and that is true for both people and machines.
- jevinskie 13y ago
  The back door would have to do some complicated pattern matching against the bitstream to identify potential "hook" or extraction points. Of course, built in crypto modules could not be trusted. I wouldn't trust much more than the LUTs! I could even see how a multiply block may be backdoored.
  - jevinskie 13y ago
    Of course, I am ignoring the proprietary tool chains in all of this. But again that depends on being able to find interesting stuff in your IP to backdoor. I would recommend using vendor IP as little as possible. Don't use a vendor Ethernet module! I could see that as a great place to attach a scan-chain backdoor.
mtgx 13y ago
Speaking of ARM, the 64 bit ARMv8 architecture is supposed to come with AES, SHA1 and SHA-256 hardware encryption.
nawitus 13y ago
I think the Chinese Loongson MIPS-based processor is 'open hardware', but I can't confirm that with a quick Google search.
- jevinskie 13y ago
  But do you trust the fab to not insert a backdoor into the CPU? How could you know? An FPGA's generality complicates backdoors.

crest 13y ago

Some FPGAs are known to have backdoors (if you have JTAG access).

ChuckMcM 13y ago
That is more like front door access but still.

kryptiskt 13y ago

> and run it in an FPGA (or if you're rich, an ASIC)? An FPGA contains way more junk than just the gate array these days. And I don't know why you would trust Xilinx or Altera (who are way more dependent on government orders than Intel) over Intel. Or any fab, for that matter. I think it's reasonable to be paranoid, but at some point one should do a cost-benefit analysis of the measures one is willing to indulge in. Because ultimately you will have to trust someone blindly, and that is true for both people and machines.

jevinskie 13y ago
The back door would have to do some complicated pattern matching against the bitstream to identify potential "hook" or extraction points. Of course, built in crypto modules could not be trusted. I wouldn't trust much more than the LUTs! I could even see how a multiply block may be backdoored.
- jevinskie 13y ago
  Of course, I am ignoring the proprietary tool chains in all of this. But again that depends on being able to find interesting stuff in your IP to backdoor. I would recommend using vendor IP as little as possible. Don't use a vendor Ethernet module! I could see that as a great place to attach a scan-chain backdoor.

mtgx 13y ago

Speaking of ARM, the 64 bit ARMv8 architecture is supposed to come with AES, SHA1 and SHA-256 hardware encryption.

nawitus 13y ago

I think the Chinese Loongson MIPS-based processor is 'open hardware', but I can't confirm that with a quick Google search.

jevinskie 13y ago
But do you trust the fab to not insert a backdoor into the CPU? How could you know? An FPGA's generality complicates backdoors.