Calculate RSA key fingerprint
The newer SSH commands will list fingerprints as a SHA256 Key.
For example:
ssh-keygen -lf ~/.ssh/id_dsa.pub
1024 SHA256:19n6fkdz0qqmowiBy6XEaA87EuG/jgWUr44ZSBhJl6Y (DSA)
If you need to compare it against an old fingerprint you also need to specify to use the MD5 fingerprint hashing function.
ssh-keygen -E md5 -lf ~/.ssh/id_dsa.pub
2048 MD5:4d:5b:97:19:8c:fe:06:f0:29:e7:f5:96:77:cb:3c:71 (DSA)
Also available: -E sha1
Update... YES...yes... I know... DSA keys for SSH should no longer be used, the older RSA key or newer ecliptic keys should be used instead.
To those 'admins' that keep editing the command I used in the above. STOP CHANGING IT! You make the command and resulting output mis-match!
To see your key on Ubuntu, just enter the following command on your terminal:
ssh-add -l
You will get an output like this:
2568 0j:20:4b:88:a7:9t:wd:19:f0:d4:4y:9g:27:cf:97:23
yourName@ubuntu (RSA)
If however you get an error like; Could not open a connection to your authentication agent.
Then it means that ssh-agent is not running. You can start/run it with:
ssh-agent bash
(thanks to @Richard in the comments) and then re-run ssh-add -l
Run the following command to retrieve the SHA256 fingerprint of your SSH key (-l
means "list" instead of create a new key, -f
means "filename"):
$ ssh-keygen -lf /path/to/ssh/key
So for example, on my machine the command I ran was (using RSA public key):
$ ssh-keygen -lf ~/.ssh/id_rsa.pub
2048 00:11:22:33:44:55:66:77:88:99:aa:bb:cc:dd:ee:ff /Users/username/.ssh/id_rsa.pub (RSA)
To get the GitHub (MD5) fingerprint format with newer versions of ssh-keygen, run:
$ ssh-keygen -E md5 -lf <fileName>
Bonus information:
ssh-keygen -lf
also works on known_hosts
and authorized_keys
files.
To find most public keys on Linux/Unix/OS X systems, run
$ find /etc/ssh /home/*/.ssh /Users/*/.ssh -name '*.pub' -o -name 'authorized_keys' -o -name 'known_hosts'
(If you want to see inside other users' homedirs, you'll have to be root or sudo.)
The ssh-add -l
is very similar, but lists the fingerprints of keys added to your agent. (OS X users take note that magic passwordless SSH via Keychain is not the same as using ssh-agent.)