Unix
Run 'ssh-keygen'.
Enter a passphrase when prompted; follow the guidelines for picking a good password in general . Unlike UNIX passwords in which (at least in many UNIXes) only the first eight characters are really used, ssh passphrases can be any length, and the longer the better.
This should create ~/.ssh/id_rsa (the private key; keep it private and do not send it to anyone) and ~/.ssh/id_rsa.pub (the public key).
add your keys to the ssh-agent's memory via 'ssh-add', followed by your passphrase
When you log in to a resource on which your public key is installed, SSH will prompt you for the passphrase for your key, rather than for a password.
Windows (assumes use of F-Secure SSH)
Bring up the F-secure client
To generate a public/private key pair, go to Edit/Settings, then select from the resulting menu Global settings/User Keys. Click on "Generate new keypair", and follow the instructions.
Click on "View public key", and you will see text that begins with this:
---- BEGIN SSH2 PUBLIC KEY ----
This text should be copied to the target machine into a file in your .ssh directory, for example $HOME/.ssh/fsecure_public_key.
Once we have installed the key, you should be able to connect through public key by selecting the File/Connect option in F-secure.
Other SSH clients have similar setup procedures. See http://www.openssh.org/windows.html for a list of freely available ssh clients for Windows.
Mac OSX
Please use the Unix key generation method above and install a Mac Utility called SSHKeyChain . SSHKeychain is a graphical front-end for ssh-agent and ssh-add on Mac OS X.
Add the execution of this utility to applications which get run at login.
Once we have installed the key, you should be able to ssh directly into systems onto which you've installed your public key and added to your key chain.