If you enable 2FA for Google Apps the shared secret is 160 bits. The google_authenticator PAM module on the other hand seems to use 80 bits for the shared secret. According to RFC 4226: R6 - The ...
We have a system that stores credit cards securely on file. We'd love to allow users to sign up using Facebook Connect or Twitter. Obviously this wouldn't be secure if we were trusting just any old ...