Celestial Software's Absolute Telnet SSH client has some great features that make it easy to configure and set up SSH authentication. The 'View Public Key' function simplifies the SSH Key extraction. The following instructions are from the Celestial Software Website:
1. Download, install, and run AbsoluteTelnet/SSH from http://www.celestialsoftware.net
2. On the Options->properties->Connection->SSH2 tab, enter the hostname and port number of your server and enable 'use smart card or USB token'
3. With the PIVKEY token still inserted, click 'View Public Key' This will bring up details of your public key and some instructions on how to install the public key to your server. These instructions may be different depending on type type of server you're using. For OpenSSH, it's as simple as appending the key to your authorized_keys file. This may require you to email the public key to your server admin or make one last connection using your password in another session to append the public key there. If you've used file-based public-key authentication, you should be familiar with this part as it is the same.
4. Once the public key has been installed on the server, you're ready to login with the smartcard. Back at the main AbsoluteTelnet/SSH screen, click the connect button to start the connection. When prompted, enter your username and the PIVKEY pin (default 000000 if you haven't changed it) Subsequent logins will not require you to re-enter the pin unless you remove and reinsert the token.