Calculate the fingerprint of an SSH public key. Part of the DevTools Surf developer suite. Browse more tools in the Security / Crypto collection.
Use Cases
Verifying SSH key identity when adding keys to remote servers
Matching fingerprints between local keys and GitHub account keys
Auditing authorized_keys files for unknown key fingerprints
Confirming key fingerprints during SSH host verification prompts
Tips
Paste your public key to calculate its SHA-256 fingerprint
Compare fingerprints to verify key identity during SSH setup
Use this to match keys listed in authorized_keys files
Fun Facts
SSH was invented by Tatu Ylonen in 1995 after a password-sniffing attack on his university network in Finland.
OpenSSH switched from MD5 to SHA-256 fingerprints by default in version 6.8, released in March 2015.
GitHub shows SSH key fingerprints in your account settings, making this tool useful for matching local keys to your GitHub profile.
FAQ
Which hash algorithm?
SHA-256 (modern default) or MD5 (legacy). OpenSSH uses SHA-256 by default since 2015. MD5 still used by some older SSH servers.
What's the fingerprint used for?
Verifying you're connecting to the intended server. First-connect warnings show the fingerprint; compare to what the server admin published.
Public or private key?
Public. Fingerprinting a private key would be a security bug — anyone with the fingerprint could check if a key they stole matches.
Can I calculate locally?
Yes: `ssh-keygen -lf ~/.ssh/id_ed25519.pub`. The tool does the same in the browser for convenience, especially when you have a key string but not the CLI.
