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

Video: Building a tool to copy-paste share terminal sessions using Claude Code for web - 23rd October 2025
Dane Stuckey (OpenAI CISO) on prompt injection risks for ChatGPT Atlas - 22nd October 2025
Living dangerously with Claude - 22nd October 2025

cryptography 22 hmac 2 security 560 sha1 4 signing 6

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