[Cryptography] Dual_EC_DRBG backdoor: a proof of concept

[Krisztián Pintér]

i think you put too much burden on a prng. all prngs need a secret
seed. it is not an argument against them. the question is, what comes
after? rephrasing: supposed that we have some secret (for example true
random), how can we expand that into a random stream in a way that we
don't introduce *new* vulnerabilities. it is not the task of the prng
to solve the seeding problem, that should be handled separately.

in that sense, BBS has the benefit of having a proof in the standard
model. as opposed to AES based generators, that have formal proof
against some attacks only, while have a general proof in the random
oracle model. again, *in addition* to the problem of the seeding,
which they also have.

i'm not claiming that this is a practical advantage, or i would pay a
dime to get that. but it certainly represents *some* value.

that said, as i heard, dual-ec does not have a security proof. correct
me if i'm wrong.


Theodore Ts'o (at Friday, January 3, 2014, 4:57:40 PM):

> Um, where are you going to get the true entropy from?  If you are
> willing to assume that you can seed the device with true entropy, then
> you can just use an AES-based CRNG.