Authentication improvements

This section is not intended to be a list of available authentication endpoints for Drupal, or a third-party integration module list. The modules included here improve the authentication mechanism. Drupal authentication is based on username and password credentials stored in the database. The user is validated against the site user list and authorized. The following modules include additional elements in the form submission or replace current fields with more secure elements. Some of the modules listed here duplicate the functionality of others.

• Swekey hardware authentication: enables swekey hardware authentication in Drupal for users and administartors. The swekey is a low cost but highly secure USB authentication USB key.
• Yubikey: YubiKey is a secure method for logging into many websites using a cryptographically secure usb token. It does not require special software, and since it does not generate the same OTP (One Time Password) more than once, nothing is shared among associated sites.
• TUPAS Authentication: Finnish banks’ Tupas certification service allows businesses and organisations providing Internet services to authenticate their customers with Tupas certificates issued by the Tupas service. In the Tupas service a bank authenticates a customer by a strong authentication method. The Tupas certificates issued by the service can also be used for signing documents electronically if so agreed by the customer and the service provider. This module provides Drupal integration to Tupas certification service and it can be used for using digital signatures to grant additional permissions for users.
• Certificate Login: Authenticate users using a certificate.
• Openid Integration: log in securely through other providers' SSL authentication using an OpenID identifier. OpenID is in core in Drupal version 6.
• OAuth: OAuth is a complete standard for external API authentication. You can integrate your Drupal site with external data from Google, Flickr, Twitter, Ma.gnolia, Yahoo and other Drupal sites that use the Web Services module. Also you can also let other sites use your site's data, by using Web Services module and OAuth as the authentication method for security.
• Site Pass: Instead of having to remember passwords users simply request a Site Pass when they need one. (This is similar to the way that airlines allow you to do on-line check-in with just an Itinerary Number instead of a username/password pair.). Checks for invalid login attempts using the Site Pass key.