eppn (eduPersonPrincipalName)

Is a standard identifier attribute that uniquely identifies a person at a campus. At UW–Madison, an ePPN is always formatted as NetID@wisc.edu. It behaves the same as a campus NetID on local systems, but it is scoped so it can work globally. It is the preferred identifier for applications that interact with federated login systems (like SAML Federation, InCommon, or eduGAIN) because it guarantees uniqueness across different universities and worldwide institutions.