Weak DH primes and openssh

Damien Miller djm at mindrot.org
Sat May 30 00:09:47 AEST 2015


On Fri, 29 May 2015, Hubert Kario wrote:

> Not really, no.
> 
> We can use this time an initial seed of "OpenSSH 1024 bit prime, attempt #1".
> Next time we generate the primes we can use the initial seed of "2017 OpenSSH 
> 1024 bit prime, attempt #1", but we can use just as well a "2nd generation 
> OpenSSH 1024 bit DH parameters, try number 1". Then we can also change the 
> algorithm to use this seed for M-R witnesses, or not. Then we can use SHA-512 
> instead of SHA-256, or some SHA-3 variant.

If you're constantly changing the parameters, then this is the opposite of
NUMS. Anyway, I don't think a NUMS-like approach is necessary. It certainly
isn't with users independently generating primality certificates.

-d


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