Publishing "Cryptographic Right Answers" for developers has become a tradition, with updates from Colin Percival in 2009, Thomas Ptacek in 2015, and Latacora in 2018 and 2024. This 2026 edition arrives early because the post-quantum transition timeline shifted sharply in early 2026, and there is now consensus that it must be completed by 2029.
The good news is that symmetric cryptography remains fine, because Grover's algorithm does not matter in practice. The bad news is that nearly all asymmetric recommendations have changed since 2018, and most have changed even since 2024. The guidance assumes no specific compliance regime, though it is largely compatible with FIPS 140. Teams bound by stricter rules such as CNSA 2.0 should substitute accordingly.
A second major change in 2026 is that LLMs are now very good at finding bugs. "Get a review from the best model you can afford" is now a Cryptographic Right Answer, joining the long-standing advice to use a memory-safe language.
For data encryption, the cheat sheet recommends the cloud KMS if you are in the cloud. Otherwise, use XAES-256-GCM or XChaCha20-Poly1305 with random nonces, and Cobblestone-128 for messages larger than a few MB. Key exchange should use X25519 combined with ML-KEM-768, and asymmetric signatures should use ML-DSA-44. Passwords should be handled with Argon2id or scrypt, though passkeys may be a better option.
Source: Hacker News · Summarized by HeadlinesBriefing