david wong

Hey ! I'm David, a security consultant at Cryptography Services, the crypto team of NCC Group . This is my blog about cryptography and security and other related topics that I find interesting.

Real World Crypto 2017: Day 1 last month

Today was the first day of Real World Crypto. My favorite con (I think I've been saying that enough). I have avoided taking long notes about this one (as I did for the previous one). But fortunately a live stream was/is available here.

The Lechvin prize was given to Joan Daemen, co-inventor of AES and SHA3, and to Moxie Marlinspike and Trevor Perrin for their work on the development on secure messaging.

Daemen talked about how block cipher might become a thing from the past, replaced by more efficient and faster permutation constructions (like the permutation-baed sponge construction they developed for SHA3).

Moxie Marlinspike gave an brilliant speech. Putting that into words would only uglify whatever was said, you will have to take my words for it.

Rich Salz gave a touching talk about the sad history of OpenSSL.

Thai Duong presented his Project Wycheproof that test java cryptographic libraries for common cryptographic pitfalls. They have something like 80 test vectors (easy to export to test other languages) and have uncovered 40+ vulnerabilities. One is being commented here.

L Jean Camp gave a talk on some X.509 statistics across phishing websites and the biggest websites (according to some akamai ranking). No full ipv4 range stats. Obviously the phishing websites were not bothering with TLS. And the speaker upset several people by saying that phishing websites should not be able to obtain certificates for similar-looking domains. Adam Langley took the mic to explain to her how orthogonal these issues were, and dropped the mic with a "we will kill the green lock".

Quan Nguyen gave a nice talk about some fun crypto vulns. Unfortunately I was dozing off, but everyone seemed to have appreciated the talk and I will be checking these slides as soon as they come up. (Some "different" ways to retrieve the authentication key from AES-GCM)

Daniel Franke presented the NTS (Network Time Security) protocol. It looks like it could protect NTP. Is it a competitor of roughtime? On the roughtime page we can read:

The obvious answer to this problem is to authenticate NTP replies. Indeed, if you want to do this there‘s NTPv4 Autokey from six years ago and NTS, which is in development. A paper at USENIX Security this year detailed how to do it so that it’s stateless at the server and still mostly using fast, symmetric cryptography.

But that's what NTP should have been, 15 years ago—it just allows the network to be untrusted. We aim higher these days.

So I guess NTS is not coming fast enough, hence the creation of roughtime. I personally like how anyone can audit roughtime servers.

Tancrède Lepoint presented on CRYSTAL, a lattice-based key exchange that seems like a competitor to New Hope. He also talked about Open Quantum Safe that contains a library of post quantum primitives as well as a fork of OpenSSL making use of this library. Someone from the public appeared to be pretty angry not to be cited first in the research, but the session chair (Dan Boneh) smoothly saved us from an awkward Q/A.

Mike Hamburg came up with STROBE, a bespoke TLS-like protocol based on one sponge construction. It targets embedded devices but isn't really focusing on speed (?) It's also heavily influenced by BLINKER and tries to improve it. It kinda felt like a competitor of the Noise Protocol Framework but looking at the paper it seems more confusing than that and much more interesting as well. From the paper:

Strobe is a framework for building cryptographic two-party protocols. It can also be used for symmetric cryptosystems such as hashing, AEAD, MACs, PRFs and PRNGs. It is also useful as the symmetric part of a Schnorr-style signature scheme.

That's it. If anyone can point me to other notes on the talks I'd gladly post a list of links in here as well:

The notes for day 2 are here.

Well done! You've reached the end of my post. Now you can leave me a comment :)

Richard Moore

You say:

And the speaker upset several people by saying that phishing websites should be able to obtain certificates for similar-looking domains.

however what I understood her to say was the opposite - she felt they should not be able to obtain such certificates. Adam's point was that there is no intention on the part of browsers (or at least chrome) that x.509 should prevent a phishing site from getting a certificate. This is pretty reasonable since if it was the intention then DV certificates would be impossible!


correct! Made a typo. Thanks for pointing that out ^^