3 ms·

NSA isn't the only or main security threat for computers. NSA, for example, is unlikely to hack your bank account and steal your money. Even if it was backdoor

NSA isn't the only or main security threat for computers. NSA, for example, is unlikely to hack your bank account and steal your money. Even if it was backdoored by the NSA, it would still be very useful for everyday threats. There are certain classes of attack that are difficult or impossible to prevent in software (think evil maid attack on full disk encryption) The reality for hardware is you have to trust the guy who fabricated it, Unfortunately since you can't fab your own 32nm chips, we are unfortunately stuck trusting that neither the Chinese MSS or NSA has hacked them.

JulianMorrison 13y ago
"if it was backdoored by the NSA" - are you going to assume it will stay backdoored by only the NSA? A vulnerability is a vulnerability.
- anologwintermut 13y ago
  Depends on how they do it . Dual_EC_DRBG is a secure random number generator if no one can solve the discrete log problem on a large curve. That's true w/ or without the NSA backdoor, since the NSA backdoor is just cheating and generated the curve with a known discrete log. This, of course, doesn't make the backdoor a good idea, and back door or not, if someone does get the discrete log for the Dual_EC_DRBG constants, you are screwed.
  - codev 13y ago
    With the known NSA backdoor in Dual_EC_DRBG then many people within the NSA must have access to the backdoor constants (even if they don't directly realise it and have access to them within an application). If Edward Snowden was willing to give up his salary and liberty for what he thought was the moral thing to do then I think it's reasonable to assume there must be many more people within the NSA who are willing to leak secrets for money or loyalty to nation states, corporations or terrorist groups. Some of those people will have given the Dual_EC_DRBG constants or applications that will crack cryptosystems using that PRNG to 'bad' actors.
    - JulianMorrison 13y ago
      Also, things leak by other means, eg: Son-Of-Stuxnet escapes into the wild with the constants in its penetration code.
a1369209993 13y ago
Actually you don't need to trust the fab: you can get a batch of identical chips, select X% at random (use dice!), grind off the packaging, examine them under a microscope, and compare what you see to the plans you sent to the fab. Proving that the plans themselves aren't backdoored (your layout software was written by whom exactly?) and aquiring a microscope that can resolve 32nm features without using any integrated circuts (which, by paranoia, we know will identify images of backdoored ICs and replace them with images of non-backdoored ones) is left as a exercise for the reader. I'm probably forgetting some other attack vectors here, actually.
- kabdib 13y ago
  Could you extend JTAG to provide verifiable hardware? I'm thinking of something like Vernor Vinge's "trusted computing" stuff in his SF book _Rainbows End_, where a flipflip took 20K gates to implement. You spend a lot of circuitry on attestation. It's probably a circular problem (who will attest to the attestors? etc.), probably devolving into digital signatures of chip layers and stuff, taken before installing CPUs an peripherals... :-/
  - anologwintermut 13y ago
    FPGA's would be a better idea and actually might be viable for a small trusted compute base.
    - xradionut 13y ago
      You would think that there would be more activity in the OpenCores and other processors on a FPGA systems, but there's not as much I expected when I researched it. Maybe the renewed revelations about the NSA will increase the participation and lower the costs.
  - harrytuttle 13y ago
    You cant trust the electrical interface to be honest if the hardware isn't honest. If a naughty processor can modify a bunch of instructions, then it can modify its verification results or whatever is provided over the interface.

JulianMorrison 13y ago

"if it was backdoored by the NSA" - are you going to assume it will stay backdoored by only the NSA? A vulnerability is a vulnerability.

anologwintermut 13y ago
Depends on how they do it . Dual_EC_DRBG is a secure random number generator if no one can solve the discrete log problem on a large curve. That's true w/ or without the NSA backdoor, since the NSA backdoor is just cheating and generated the curve with a known discrete log. This, of course, doesn't make the backdoor a good idea, and back door or not, if someone does get the discrete log for the Dual_EC_DRBG constants, you are screwed.
- codev 13y ago
  With the known NSA backdoor in Dual_EC_DRBG then many people within the NSA must have access to the backdoor constants (even if they don't directly realise it and have access to them within an application). If Edward Snowden was willing to give up his salary and liberty for what he thought was the moral thing to do then I think it's reasonable to assume there must be many more people within the NSA who are willing to leak secrets for money or loyalty to nation states, corporations or terrorist groups. Some of those people will have given the Dual_EC_DRBG constants or applications that will crack cryptosystems using that PRNG to 'bad' actors.
  - JulianMorrison 13y ago
    Also, things leak by other means, eg: Son-Of-Stuxnet escapes into the wild with the constants in its penetration code.

a1369209993 13y ago

Actually you don't need to trust the fab: you can get a batch of identical chips, select X% at random (use dice!), grind off the packaging, examine them under a microscope, and compare what you see to the plans you sent to the fab. Proving that the plans themselves aren't backdoored (your layout software was written by whom exactly?) and aquiring a microscope that can resolve 32nm features without using any integrated circuts (which, by paranoia, we know will identify images of backdoored ICs and replace them with images of non-backdoored ones) is left as a exercise for the reader. I'm probably forgetting some other attack vectors here, actually.

kabdib 13y ago
Could you extend JTAG to provide verifiable hardware? I'm thinking of something like Vernor Vinge's "trusted computing" stuff in his SF book _Rainbows End_, where a flipflip took 20K gates to implement. You spend a lot of circuitry on attestation. It's probably a circular problem (who will attest to the attestors? etc.), probably devolving into digital signatures of chip layers and stuff, taken before installing CPUs an peripherals... :-/
- anologwintermut 13y ago
  FPGA's would be a better idea and actually might be viable for a small trusted compute base.
  - xradionut 13y ago
    You would think that there would be more activity in the OpenCores and other processors on a FPGA systems, but there's not as much I expected when I researched it. Maybe the renewed revelations about the NSA will increase the participation and lower the costs.
- harrytuttle 13y ago
  You cant trust the electrical interface to be honest if the hardware isn't honest. If a naughty processor can modify a bunch of instructions, then it can modify its verification results or whatever is provided over the interface.