Simon Willison’s Weblog

Don't Hash Secrets. A well written explanation from 2008 of why you must use hmac instead of raw SHA-1 when hashing against a secret.

Posted 24th January 2010 at 1:30 pm

Recent articles

Introducing gisthost.github.io - 1st January 2026
2025: The year in LLMs - 31st December 2025
How Rob Pike got spammed with an AI slop "act of kindness" - 26th December 2025

cryptography 24 hmac 2 security 571 sha1 4 signing 6

Monthly briefing

Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments.

Pay me to send you less!

Sponsor & subscribe