[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
Re: Initial entropy with no HWRNG
[trimming cc list to tech-crypto]
> Date: Tue, 12 May 2020 11:45:58 -0400
> From: Thor Lancelot Simon <tls%panix.com@localhost>
> 1) It's hard to understand how many bits of entropy to assign to a
> sample from one of these sources. [...]
> The delta estimator _was_ good for these things, particularly for
> things like fans or thermistors (where the macroscopic,
> non-random physical processes _are_ expected to have continuous
> behavior), because it could tell you when to very conservatively
> add 1 bit.
What is the model you're using to justify this claim that actually
bears some connection to the physical devices involved?
Without a physically justifiable model -- one that generally works on
_all_ hardware of any type that a driver supports -- or a claim from a
vendor about what's going on in the device, that's not something we
should be fabricating from whole cloth and foisting on users.
> B) One thing we *could* do to help out such systems would be to actually run
> a service to bootstrap them with entropy ourselves, from the installer,
> across the network. Should a user trust such a service? I will argue
> "yes". Why?
> B1) Because they already got the binaries or the sources from us; we could
> simply tamper those to do the wrong thing instead.
Tampering is loud, but eavesdropping is quiet. There is no way to do
this that is resistant to eavesdropping without a secret on the client
(This would also make TNF's infrastructure a much juicier target,
because it would grant access to the keys on anything running a new
NetBSD installation without requiring tampering.)
Main Index |
Thread Index |