Subject: [TLS] What's up with TACK?

From: Aaron Zauner <[email-masked]>
Date: Sat, 13 Jun 2015 21:34:45 +0200

Hey,

I've been meaning to write this message for almost a year now. I've
not seen any recent discussion on generic key pinning on this list.

We now have HPKP support in major browsers but protocols like
STARTTLS are still left our when it comes to pinning. Discussion on
TACK seemed to have died during the HPKP proposal somehow, yet it's
the more elegant, generic approach to key pinning in TLS. Although
the spec is confusing I have no problem with HPKP as is and I'm
happy that it's in roll-out phase.

I'd like to see discussion on TACK again. Actually I don't
understand why this proposal was never adopted by the WG.

Thanks for your time,
Aaron

---

From: Hanno Böck <[email-masked]>
Date: Thu, 18 Jun 2015 13:20:41 +0200

I'm a bit surprised that nobody seems to care to answer here.

CA failures still happen on a quite regular basis. We recently had
CNNIC, ANSSI and India CCA. I think this is the elephant in the room of
TLS problems.

HPKP makes me have very mixed feelings. On the one hand I'm happy that
we have something at last, but on the other hand I fear that people
might move into the "we now have a solution for HTTPS" direction and
neglect other uses of TLS. I'd be worried if we consider non-HTTPS-TLS
a second-best security solution.

Also from my understanding TACK also solves another problem:
STARTTLS-stripping (draft, chapter 5.2), which is as far as I'm aware
also otherwise an unsolved issue (see e.g. [1]).

In other words: I support Aarons request to adopt TACK or something
similar.

[1] https://blog.filippo.io/the-sad-state-of-smtp-encryption/
-- 
Hanno Böck
http://hboeck.de/

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