If you’re a normal person — that is, a person who doesn’t obsessively follow the latest cryptography news — you probably missed last week’s cryptography bombshell. That news comes in the form of a new e-print authored by Yilei Chen, “Quantum Algorithms for Lattice Problems“, which has roiled the cryptography research community. The result is now being...

It’s been a while since I wrote an “attack of the week” post, and the fault for this is entirely mine. I’ve been much too busy writing boring posts about Schnorr signatures! But this week’s news brings an exciting story with both technical and political dimensions: new reports claim that Chinese security agencies have developed a technique to trace...

This post continues a long, wonky discussion of Schnorr signature schemes and the Dilithium post-quantum signature. You may want to start with Part 1. In the previous post I discussed the intuition behind Schnorr signatures, beginning with a high-level design rationale and ending with a concrete instantiation. As a reminder: our discussion...

Warning: extremely wonky cryptography post. Also, possibly stupid and bound for nowhere. One of the hardest problems in applied cryptography (and perhaps all of computer science!) is explaining why our tools work the way they do. After all, we’ve been gifted an amazing basket of useful algorithms from those who came before us. Hence it’s perfectly...

Recently a reader wrote in and asked if I would look at Sam Altman’s Worldcoin, presumably to give thoughts on it from a privacy perspective. This was honestly the last thing I wanted to do, since life is short and this seemed like an obvious waste of it. Of course a project devoted to literally scanning your eyeballs was up to some bad things, duh....

Back in March I was fortunate to spend several days visiting Brussels, where I had a chance to attend a panel on “chat control“: the new content scanning regime being considered by the EU Commission. Among various requirements, this proposed legislation would mandate that client-side scanning technology be incorporated into encrypted text messaging...