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NSA and IETF, part 3: Dodging the issues at hand

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171–180 of 249 posts

Re: NSA and IETF, part 3: Dodging the issues at hand

#171

Earlier quoted context omitted.

yes dragon blood. I’m not speaking of the downgrade but the timing sidechannels — which were called out very loudly and then ignored during standardization. and then the PAKE showed up in wpa3 of all places, that was the key issue and was extended further in a brain pool curve specific attack for the proposed initial mitigation. It’s a good example of error by committee I do not address that article and don’t know wh…

Aren't the timing attacks you're talking about specific to oddball parameters for the handshake? If you're doing Dragonfly with Brainpool curves you're specifically not doing what NSA wants you to do. Brainpool curves are literally a rejection of NIST's curves. If you haven't read the Enigma paper, you should do so before confidently stating that nobody's done "sanity checks" on the P-curves. Its authors are approxim…

Ah now I see what the question was as it seemed like a non sequitur. I misunderstood the comment by foxboron to be concerns about any backdoors not that P256 is backdoored, I hold no such view of that, surely bitcoin should be good evidence.

Instead I was stating that weaknesses in cryptography have been historically put there with some NSA involvement at times.

For DB: The brain pool curves do have a worse leak, but as stated in the dragon blood paper “we believe that these sidechannels are inherent to Dragonfly”. The first attack submission did hit P-256 setups before the minimal iteration count was increased and afterward was more applicable to same-system cache/ micro architectural bugs. These attacks were more generally correctly mitigated when H2C deterministic algorithms rolled out. There’s many bad choices that were selected of course to make the PAKE more exploitable, putting the client MAC in the pre commits, having that downgrade, including brain pool curves. but to my point on committees— cryptographers warned strongly when standardizing that this could be an attack and no course correction was taken.

Re: NSA and IETF, part 3: Dodging the issues at hand

#172

Earlier quoted context omitted.

Within the IETF it’s not 100%. See section 3.3 of one of their RFCs for proof. https://www.rfc-editor.org/rfc/rfc2418.html#section-3.3 “ Working groups make decisions through a "rough consensus" process. IETF consensus does not require that all participants agree although this is, of course, preferred. In general, the dominant view of the working group shall prevail. (However, it must be noted that "dominance" is not…

That's "rough consensus" as opposed to "consensus".

And that’s what the IETF uses but djb doesn’t like.

Re: NSA and IETF, part 3: Dodging the issues at hand

#173

Earlier quoted context omitted.

> No, the argument is that the algorithm (as specified in the standard) is difficult to implement correctly, so we should tweak it/find another one. This argument is without merit. ML-KEM/Kyber has already been ratified as the PQC KEM standard by NIST. What you are proposing is that the NIST process was fundamentally flawed. This is a claim that requires serious evidence as backup.

You can't be serious. "The standard was adopted, therefore it must be able to be implemented in any or all systems?" NIST can adopt and recommend whatever algorithms they might like using whatever criteria they decide they want to use. However, while the amount of expertise and experience on display by NIST in identifying algorithms that are secure or potentially useful is impressive, there is no amount of expertise…

> You can't be serious. "The standard was adopted, therefore it must be able to be implemented in any or all systems?"

If we did that we'd all be using Dual_EC...

Re: NSA and IETF, part 3: Dodging the issues at hand

#174

Earlier quoted context omitted.

> No, the argument is that the algorithm (as specified in the standard) is difficult to implement correctly, so we should tweak it/find another one. This argument is without merit. ML-KEM/Kyber has already been ratified as the PQC KEM standard by NIST. What you are proposing is that the NIST process was fundamentally flawed. This is a claim that requires serious evidence as backup.

DJB has specific (technical and non-conspiratorial) bones to pick with the algorithm. He’s as much an expert in cryptographic implementation flaws and misuse resistance as anybody at NIST. Doesn’t mean he’s right all the time, but blowing him off as if he’s just some crackpot isn’t even correctly appealing to authority. I hate that his more tinfoil hat stuff (which is not totally unjustified, mind you) overshadows hi…

> I hate that his more tinfoil hat stuff (which is not totally unjustified, mind you) overshadows his sober technical contributions in these discussions.

Currently he argues that NSA is likely to be attacking the standards process to do some unspecified nefarious thing in PQ algorithms, and he's appealing to our memories of Dual_EC. That's not tinfoil hat stuff! It's a serious possibility that has happened before (Dual_EC). True, no one knows for a fact that NSA backdoored Dual_EC, but it's very very likely that they did -- why bother with such a slow DRBG if not for this benefit of being able to recover session keys?

Re: NSA and IETF, part 3: Dodging the issues at hand

#175

Earlier quoted context omitted.

> No, the argument is that the algorithm (as specified in the standard) is difficult to implement correctly, so we should tweak it/find another one. This argument is without merit. ML-KEM/Kyber has already been ratified as the PQC KEM standard by NIST. What you are proposing is that the NIST process was fundamentally flawed. This is a claim that requires serious evidence as backup.

You can't be serious. "The standard was adopted, therefore it must be able to be implemented in any or all systems?" NIST can adopt and recommend whatever algorithms they might like using whatever criteria they decide they want to use. However, while the amount of expertise and experience on display by NIST in identifying algorithms that are secure or potentially useful is impressive, there is no amount of expertise…

I'm having trouble understanding your argument. Elliptic curve algorithms have been the mainstream standard for key establishment for something like 15 years now. The NIST standards for the P-curves are much, much older than 8 years.

Re: NSA and IETF, part 3: Dodging the issues at hand

#176

Earlier quoted context omitted.

DJB has specific (technical and non-conspiratorial) bones to pick with the algorithm. He’s as much an expert in cryptographic implementation flaws and misuse resistance as anybody at NIST. Doesn’t mean he’s right all the time, but blowing him off as if he’s just some crackpot isn’t even correctly appealing to authority. I hate that his more tinfoil hat stuff (which is not totally unjustified, mind you) overshadows hi…

> I hate that his more tinfoil hat stuff (which is not totally unjustified, mind you) overshadows his sober technical contributions in these discussions. Currently he argues that NSA is likely to be attacking the standards process to do some unspecified nefarious thing in PQ algorithms, and he's appealing to our memories of Dual_EC. That's not tinfoil hat stuff! It's a serious possibility that has happened before (Du…

NSA wrote Dual EC. A team of (mostly European) academic cryptographers wrote the CRYSTALS constructions. Moreover, the NOBUS mechanism in Dual EC is obvious, and it's not at all clear where you'd do anything like that in Kyber, which goes out of its way not to have the "weird constants" problem that the P-curves (which practitioners generally trust) ended up with.

Re: NSA and IETF, part 3: Dodging the issues at hand

#177

Earlier quoted context omitted.

That's "rough consensus" as opposed to "consensus".

And that’s what the IETF uses but djb doesn’t like.

It's literally the ethos of the IETF going back to (at least) the late 1980s, when this was the primary contrast between IETF standards process vs. the more staid and rigorous OSI process. It's not usefully up for debate.

Re: NSA and IETF, part 3: Dodging the issues at hand

#178

Earlier quoted context omitted.

Aren't the timing attacks you're talking about specific to oddball parameters for the handshake? If you're doing Dragonfly with Brainpool curves you're specifically not doing what NSA wants you to do. Brainpool curves are literally a rejection of NIST's curves. If you haven't read the Enigma paper, you should do so before confidently stating that nobody's done "sanity checks" on the P-curves. Its authors are approxim…

Ah now I see what the question was as it seemed like a non sequitur. I misunderstood the comment by foxboron to be concerns about any backdoors not that P256 is backdoored, I hold no such view of that, surely bitcoin should be good evidence. Instead I was stating that weaknesses in cryptography have been historically put there with some NSA involvement at times. For DB: The brain pool curves do have a worse leak, but…

Can I ask you to respond to the "sanity check" argument you made upthread? What is the "sanity checking" you're implying wasn't done on the P-curves?

Re: NSA and IETF, part 3: Dodging the issues at hand

#179
post #21

Amongst the numerous reasons why you _don't_ want to rush into implementing new algorithms is even the _reference implementation_ (and most other early implementations) for Kyber/ML-KEM included multiple timing side channel vulnerabilities that allowed for key recovery.[1][2] djb has been consistent in view for decades that cryptography standards need to consider the foolproofness of implementation so that a minor im…

> See for example the many problems of NIST P-224/P-256/P-384 ECC curves What are those problems exactly? The whitepaper from djb only makes vague claims about NSA being a malicious actor, but after ~20 years no known backdoors nor intentional weaknesses has been reliably proven?

Dual_EC's backdoor can't be proven, but it's almost certainly real.

Re: NSA and IETF, part 3: Dodging the issues at hand

#180
post #82

Earlier quoted context omitted.

> See for example the many problems of NIST P-224/P-256/P-384 ECC curves What are those problems exactly? The whitepaper from djb only makes vague claims about NSA being a malicious actor, but after ~20 years no known backdoors nor intentional weaknesses has been reliably proven?

As I understand it, a big issue is that they are really hard to implement correctly. This means that backdoors and weaknesses might not exist in the theoretical algorithm, but still be common in real-world implementations. On the other hand, Curve25519 is designed from the ground up to be hard to implement incorrectly : there are very few footguns, gotchas, and edge cases. This means that real-world implementations a…

I tried to defend a similar argument in a private forum today and basically got my ass handed to me. In practice, not only would modern P-curve implementations not be "significantly weaker" than Curve25519 (we've had good complete addition formulas for them for a long time, along with widespread hardware support), but Curve25519 causes as many (probably more) problems than it solves --- cofactor problems being more common in modern practice than point validation mistakes.

In TLS, Curve25519 vs. the P-curves are a total non-issue, because TLS isn't generally deployed anymore in ways that even admit point validation vulnerabilities (even if implementations still had them). That bit, I already knew, but I'd assumed ad-hoc non-TLS implementations, by random people who don't know what point validation is, might tip the scales. Turns out guess not.

Again, by way of bona fides: I woke up this morning in your camp, regarding Curve25519. But that won't be the camp I go to bed in.

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