This project is now obsolete and will be archived as Salesforce now provides these features natively. See Verify Your Identity with a TOTP Authenticator App.
Apex Classes that implement:
TOTP: Time-Based One-Time Password Algorithm http://tools.ietf.org/html/rfc6238
HOTP: An HMAC-Based One-Time Password Algorithm http://www.ietf.org/rfc/rfc4226.txt
These are the raw algorithms, and and do not support registration or storage functions for the shared secrets.