applied cryptography @Meta

Menlo Park, CA
Joined December 2018
AKD (WhatsApp's key transparency library) was recently audited by NCC Group. Thanks to Elena Bakos-Lang, @gerald_doussot, Kevin Henry, @BearSSLnews, and others for the great work on this!
New Blog: Public Report – WhatsApp Auditable Key Directory (AKD) Implementation Review research.nccgroup.com/2023/1…
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We've made our library publicly available in the hopes that other encrypted messaging apps looking to deploy key transparency to a large user base can do so more easily -- github.com/facebook/akd Open to PRs and general feedback!
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under-remarked in this Apple announcement is the fact that for the first time in a decade or more, there is now an aspect in which Signal is behind the state of the art in secure messaging. huge congrats to the team, it’s a massive leap forward! security.apple.com/blog/imes…
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Oh wow, key transparency is coming to iMessage? 🤯 security.apple.com/blog/imes…
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There will be 1000 write-ups criticizing the technology, approach, or distribution of @worldnetwork. In fact, it's pretty easy to do this for any person with crypto/security background. + You'll get a lot of media attention. But I think it's important to take a step back, imagine the potential of what if this actually works, understand the technical limitations, and see how we can solve one problem at a time. The project is still in the early phases of development. After browsing the docs for a few hours (they're very good for an early-stage project), here're a few low hanging recommendations to the team. * Make the audits public. Seems there were two audits done by Nethermind & Least Authority. The audits are not public yet. whitepaper.worldcoin.org/oth… * Run public security contests and bug bounties. e.g., using @immunefi and @code4rena. * Clearly state the assumptions. In any crypto/security system, it's important to understand the roots of trust. The assumptions should be of the form: "We trust that (a) the Orb is not compromised, (b) the PKI around the Orb is secure, (c) the ZK proof by Groth16 is secure, (d) the user's device storing the key is secure, etc." * State the assumptions around the Orb. e.g., The Orb generates an iris code of length X such that for all scans of all Orbs of the same person, the Hamming distance between any two pairs of scans is < Y, and for all pairs of iris scans that belong to different people, the Hamming distance is greater than Z. * It wasn't clear to me where the iris data is stored and not stored. Make that very explicit. Which devices / services have access to the full iris data vs its fingerprint? Is the fingerprint lossy or cryptographically secure? [i.e., no info about the pre-image, the iris sequence itself, can be extracted from the public info (statistically) vs its protected using crypto and holds private under some crypto assumptions]. * Anticipating a backlash of academic papers breaking the protocol, pro-actively engage with them. e.g., create research grants for folks to write a paper breaking some part of the protocol && suggesting a way to fix and improve it. * Start an open-source research / development program for alternatives to the Orb hardware implementation. cc @mnovendstern, @sama , @chriswaclawek
Going forward, the Hamming distance between your eyeballs and mine will be used to differentiate us. This will be fun. cc @worldnetwork
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Excited to announce the 1st Workshop on Cryptography Applied to Transparency Systems (CATS)! Nov 30, 2023, co-located with ACM CCS in Copenhagen. Submissions due Sept 1. More details here: catsworkshop.dev/
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There's some neat behind-the-scenes crypto involved to link WhatsApp E2EE sessions across devices... without QR codes!
📝 WhatsApp beta for Android 2.23.14.18: what's new? WhatsApp is rolling out a feature to link your account to WhatsApp Web by using your phone number, and it's available to some beta testers! wabetainfo.com/whatsapp-beta…
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If Github Actions were backed by TEEs that provided remote attestation, couldn't we use them for things like trusted execution of smart contracts? Seems easier than the setup today where organizations need to build their own custom infra for dealing with SGX, at least...
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Great work and congrats, very much looking forward to this at CRYPTO!
Our paper "Security Analysis of the @WhatsApp End-to-End Encrypted Backup Protocol" has been accepted to CRYPTO 2023. We provide the first formal security analysis of the WhatsApp backup protocol in the UC framework. Full version available here: eprint.iacr.org/2023/843 1/3
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NEW EPISODE Are Twitter’s new encrypted DMs unreadable even if you put a gun to Elon’s head? We invited @mjg59 on to do a deep dive into what kind of cryptography actually shipped. securitycryptographywhatever… podcasts.apple.com/us/podcas…
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Today, we (@WhatsApp) announced our plans to deploy key transparency, as a way for users to be able to verify each other’s public keys “automatically”. Lots of details go into this, and are described in this blog post here: engineering.fb.com/2023/04/1… 🧵
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...But this is by no means the end of the story for key transparency. There are still lots of improvements to be made to these existing protocols, and new questions to consider in real-world settings.
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We hope that WhatsApp’s intent to deploy key transparency can help to spur on further academic research in this important area, and also for other encrypted messaging apps to adopt key transparency as well!
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