SHA-1 Hash Generator

This tool is completely free and ad-free. It's built by the maker of StatusHarbor - uptime monitoring with public status pages for your services. If you're generating IDs for something you're building, StatusHarbor will tell you the moment it goes down.

SHA-1 is also broken for security use. The SHAttered attack published a real collision in 2017, and the 2020 chosen-prefix attack brought the cost down far enough that forging a SHA-1 signature is a budget question, not a research question. Browsers stopped trusting SHA-1 certificates years ago, and NIST has formally retired it.

It still appears everywhere because it is baked into older systems. Git names objects by SHA-1, older TLS and SSH configurations negotiate it, and plenty of internal APIs sign requests with HMAC-SHA1. HMAC-SHA1 is a special case: the collision attacks do not directly break it, so it is not an emergency, but there is no reason to choose it for anything new.

For a new design pick SHA-256. Use this page when you need to reproduce a SHA-1 value that some existing system already expects - matching a Git object id, debugging a legacy signature, or checking an old checksum file.