To enable someone to ssh into 'remotehost' as user 'jrandom', you append their SSH public key to the file ~jrandom/.ssh/authorized_keys on remotehost. Their username on their local box doesn't have to be the same as the remote username. For example, adding someone's SSH public key to ~root/authorized_keys on remotehost means they can do ssh root@remotehost.example.com So, where do they get their public key from? The public key is a single line, the contents of ~/.ssh/id_rsa.pub on their *local* machine. If that file's not there, then try ~/.ssh/id_dsa.pub. RSA and DSA are two different public key cryptosystems, but RSA is better, so they should use that if available. If neither is available, they can use the command ssh-keygen (run that only on a trusted box, of course) to generate a new public/private keypair. Note the single line that needs to be pasted is very long -- hundreds of characters.