The Google Authenticator package contains a plug-able authentication module (PAM) which allows login using one-time pass-codes conforming to the open standards developed by the Initiative for Open Authentication (OATH) (which is unrelated to OAuth). Pass-code generators are available (separately) for several mobile platforms. These implementations support the HMAC-Based One-time Password (HOTP) algorithm specified in RFC 4226 and the Time-based One-time Password (TOTP) algorithm currently in draft.
|google-authenticator||initialize one-time passcodes for the current user|
|pam_google_authenticator||PAM module for Google two-factor authentication|