S/Key

S/Key (which stands for "Secure Key") is a way to keep passwords safe. It uses something called "one-time passwords". This means that every time you type in your password it will be different. That way, even if someone is trying to guess your password, they won't be able to guess what it will be next time. S/Key also stores these passwords in a way that makes them hard to guess or crack. That way, your passwords will stay safe.