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

I think "agent" may finally have a widely enough agreed upon definition to be useful jargon now - 18th September 2025
My review of Claude's new Code Interpreter, released under a very confusing name - 9th September 2025
Recreating the Apollo AI adoption rate chart with GPT-5, Python and Pyodide - 9th September 2025

cryptography 22 hmac 2 security 546 sha1 4 signing 6

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