I wrote a short document describing how I maintain open source projects, to link it from my global CODE_OF_CONDUCT, CONTRIBUTING, and SECURITY files. It talks about how I prefer issues to PRs, how I work in batches, and how I'm trigger-happy with bans. It's all about setting expectations. It got some unexpected attention, so I'm sharing it with my...

I’m a big fan of technologies that enable otherwise impossible security properties and user experiences, like cryptography often can. One such technology is hardware secure elements. Here’s a thing you can’t do with cryptography: encrypt data securely with a low-entropy secret, like a PIN. If a high-speed brute-force attack is possible, you need a...

filippo.io/mlkem768 is a pure-Go implementation of ML-KEM-768 optimized for correctness and readability. ML-KEM (formerly known as Kyber, renamed because we can’t have nice things) is a post-quantum key exchange mechanism in the process of being standardized by NIST and adopted by most of the industry. The package amounts to ~500 lines of code, plus...

I was once talking with a mathematician and trying to explain elliptic curve cryptography. Eventually, something clicked and they went "oh, that! I think there was a chapter about it in the book. You made a whole field out of it?" Yes, in cryptography we end up focusing on a very narrow slice of the general math we use. I think that's good, and makes...

With all the talk recently of how the NIST curve parameters were selected, a reasonable observer could wonder why we all use the same curves instead of generating them along with keys, like we do for Diffie-Hellman parameters. (You might have memories of waiting around for openssl dhparam to run and then configuring the result in a web server for TLS.)...

The NIST elliptic curves that power much of modern cryptography were generated in the late ‘90s by hashing seeds provided by the NSA. How were the seeds generated? Rumor has it that they are in turn hashes of English sentences, but the person who picked them, Dr. Jerry Solinas, passed away in early 2023 leaving behind a cryptographic mystery, some conspiracy...