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Comment by digitalPhonix | Hacker News Reader

This post makes a bad argument.

Saying that there's no "Nobody but us backdoor" to prove there's *no* backdoor of *any kind* is clearly naive at best, dishonest at worst.

As an example - if there's a weakness that affects 50% of keys (replace with whatever hypothetical number), NSA can make sure it doesn't use those affected keys but still retain the ability to decrypt 50% of everyone else's communications. And using the entropy analysis from this post, that would require 1 bit hidden in the parameters which is clearly within the entropy budget.

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A NOBUS backdoor in an asymmetric primitive that looks like "X% of all keys is weak" would not explain "let's move the entire fucking federal governnent to this algorithm including implementations sourced by the private sector that don't do our secret sauxe".

Dual_EC_DRBG is the shape of backdoor that would need to apply here: even if you knew the structure of it, you would need an additional private number to attack it. Recall the Juniper vulnerability where another threat actor simply replaced the EC public key used by Juniper's Dual_EC implementation.

NOBUS without some mathematical assurance that, even should an adversary discover the same break through, they cannot decrypt the same traffic would be too risky when you consider the NSA's self interest and dual mission.

> A NOBUS backdoor in an asymmetric primitive that looks like "X% of all keys is weak"

That’s not a NOBUS backdoor. It’s a different type of backdoor and I’m pointing out that proving there is no NOBUS backdoor doesn’t mean there’s no other backdoor.

It’s a counterexample that I came up with in 5 minutes, not a proof that it’s useful to a state actor.

Why would they use a backdoor that isn't NOBUS?

And why would they still be migrating top secret communications towards the algorithm they (NOBUS or not) have a backdoor in?

That doesn't sound very COMINT to me.

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