Benchmarking RSA Key Generation

RSA key generation is both conceptually simple, and one of the worst implementation tasks of the field of cryptography engineering. Even benchmarking it is tricky, and involves some math: here’s how we generated a stable but representative “average case” instead of using the ordinary statistical...

Let’s All Agree to Use Seeds as ML-KEM Keys

Last week, NIST published the final version of the ML-KEM1 specification, FIPS 203. One change from the draft is that the final document explicitly allows storing the private decapsulation key as a seed. This is a plea to the cryptography engineering community: let’s all agree to only use seeds a...

Why We Don’t Generate Elliptic Curves Every Day

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 a...

A Wide Reduction Trick

In line with the original spirit of Cryptography Dispatches, this is a quick1 issue to talk about a neat bit of cryptography engineering I encountered. The structure of an ECC implementation Elliptic curve cryptography implementations all roughly share the following structure: theres a base field...

Reconstruct Instead of Validating

Project Zero dropped a great bug in Vault which I think would have been prevented by one of the lessons learned of cryptography engineering: when you can, always prefer reconstructing a value rather than parsing and validating it. You should read the blog post to understand the attack first,...

Three of My Books Are Available in DRM-Free E-Book Format

Humble Bundle sells groups of e-books at ridiculously low prices, DRM free. This month, the bundles are all Wiley titles, including three of my books: Applied Cryptography, Secrets and Lies, and Cryptography Engineering. $15 gets you everything, and they're all DRM-free. Even better, a portion of...