Systems and methods for associating multiple credentials with a single
user account in a distributed authentication system. A user can be
authenticated to a service by providing any one of the multiple
credentials to the authentication system. Thus, a user can provide
credentials that are more easily entered or supplied on a given device.
All of the credentials are associated with a single user account. The
credentials can be associated symmetrically, where the user account is
independent of each credential, or asymmetrically, where the user account
is stored with a primary credential and the other credentials are
secondary credentials that reference the primary credential.