SecurID

A one time password system. Users are issued a credit card-sized smart card with an LCD on the front. The card has a precise clock that is synchronized to a clock on the server. The card and the server both generate numbers based on time elapsed; each number is only valid for a short time period and is used as a password during part of login.

Supplied by RSA Security. http://www.rsasecurity.com/

SecurID is no longer limited to a hardware solution, software, hardware, SmartCard and Palm based solutions are also offered.

Offered with a programming API, SecurID can be used for authenication in almost any environment, for example RAS, Firewall authentication, banking applications and so on.

Unfortunately AOL also use SecurID for their CRIS application, which is rather easy to slide into.