In the last issue of the
Linux Journal, there is an article about the
YubiKey. The YubiKey is providing One-Time-Passwords login, in a way Vasco and RSA do as well with their tokens. Although the YubiKey is working on (almost) any operating system (Linux/Mac/Windows/...).
It's very easy to use, plug it in the USB-port and press the button. This will generates a 16bytes block. Together with the other open source tools of Yubico, you will be able to implement two-factor authentication.
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So I will buy a YubiKey, to play around with 
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