guard bash

guard bash is a shell wrapper that will execute an authentication phase before any command is executed. It uses a secret (user owned) algorithm method, and has a per user customizable procedure. If you need to connect to your computer from outside of your safe environment, even if you use SSH, you are vulnerable to simple attacks like key sniffing or to more complex attacks against SSH. If you have more than just one authentication method, you can more safely log in your account from an insecure Internet host.