scope:

This document describes an abstract mechanism for delivering root keys from an Extensible Authentication Protocol (EAP) server to another network server that requires the keys for offering security protected services, such as re-authentication, to an EAP peer. The distributed root key can be either a usage-specific root key (USRK), a domain-specific root key (DSRK), or a domain-specific usagespecific root key (DSUSRK) that has been derived from an Extended Master Session Key (EMSK) hierarchy previously established between the EAP server and an EAP peer. This document defines a template for a key distribution exchange (KDE) protocol that can distribute these different types of root keys using a AAA (Authentication, Authorization, and Accounting) protocol and discusses its security requirements. The described protocol template does not specify message formats, data encoding, or other implementation details. It thus needs to be instantiated with a specific protocol (e.g., RADIUS or Diameter) before it can be used.