For google, I turned on two-factor authentication. The provide an iOS/Android/Blackberry app that acts like a secureId (provides a different security code every 30 seconds).
The phone app could be also be used for your own projects. It supports multiple accounts and either manual or QR-code based configuration.
Google provides a PAM module so you can add 2-factor auth to ssh. And it is easy to implement the standard on the server side, if you want to add 2-factor auth to your web app.
Comments
For google, I turned on two-factor authentication. The provide an iOS/Android/Blackberry app that acts like a secureId (provides a different security code every 30 seconds).
The phone app could be also be used for your own projects. It supports multiple accounts and either manual or QR-code based configuration.
Google provides a PAM module so you can add 2-factor auth to ssh. And it is easy to implement the standard on the server side, if you want to add 2-factor auth to your web app.
For more info, see:
http://code.google.com/p/google-authenticator/