In the tradition started by Colin Percival and Thomas Ptacek, a set of “Cryptographic Right Answers” updated for the accelerated post-quantum transition timeline.

I am publishing a production, pure-Python ML-DSA verifier. It's just 350 lines, and pretty readable and robust.

Passkey records are an interoperable format for WebAuthn credentials, similar to password hash strings. I propose a potential crypto/passkey Go API based on them.

We needed the insight and confidentiality to protect our users, but now that anyone can get the same results from LLM?

There is no need to update symmetric key sizes as part of the post-quantum transition, due to the details of how Grover's algorithm scales. Most authorities agree.

The risk that cryptographically-relevant quantum computers materialize within the next few years is now high enough to be dispositive, unfortunately.

I recommend turning Dependabot off and replacing it with a pair of scheduled GitHub Actions, one running govulncheck, and the other running CI against the latest version of your dependencies.

Code hosts like GitHub don't necessarily show the correct source of Go modules. pkg.geomys.dev is a new convenient viewer for module source.

In Go, go.mod acts as both manifest and lockfile. There is never a reason to look at go.sum.

We apply a transparency log to a centralized keyserver step-by-step, in less than 500 lines, with privacy protections, anti-poisoning, and witness cosigning.

I delivered my traditional Go Cryptography State of the Union talk at GopherCon US 2025 in New York. It goes into everything that happened at the intersection of Go and cryptography over the last year.

Surprisingly (to me) Claude Code debugged my new ML-DSA implementation faster than I would have, finding the non-obvious low-level issue that was making Verify fail.

Introducing the set of standards that Geomys maintainers strive to uphold in our professional activity as open source maintainers.

Project compromises have common root causes we can mitigate: phishing, control handoff, and unsafe GitHub Actions triggers.

Geomys sometimes acts as a maintainer of last resort for critical Go projects. Recently, we took over the bluemonday HTML sanitizer, and built upgrade paths for the gorilla/csrf library.

Cross-Site Request Forgery countermeasures can be greatly simplified using request metadata provided by modern browsers.