Access Control - Biometric and Federated Identity

There are different types of biometric systems in the industry today. Some make authentication decision based on behavior and some make authentication decisions based on physical attributes. However, a system that uses physical attributes provides more accuracy than one that uses behavior attributes. This is because
A biometric system can make authentication decisions based on an individual's behavior, as in signature dynamics and voice prints, but these can change over time and possibly be forged. Biometric systems that base authentication decisions on physical attributes (iris, retina, fingerprint) provide more accuracy, because they do not change as often and are harder to impersonate.

A federated identity is a portable identity, and its associated entitlements, that can be used across business boundaries. It allows a user to be authenticated across multiple IT systems and enterprises. Identity federation is based upon linking a user's otherwise distinct identities at two or more locations without the need to synchronize or consolidate directory information. Federated identity offers businesses and consumers a more convenient way of accessing distributed resources and is a key component of e-commerce. It is essentially when one organization agrees to trust another organization's authentication of a user, and provide them a degree of access based on that authentication.