What is an Extended Master Session Key (EMSK)?
EMSK is additional keying material that is exported by the EAP method. EMSK is at least 64 octets in length. EMSK is shared between the EAP client and server, but is not shared with the authenticator or any other third party. Currently, EMSK is reserved for future use. For more information, see Extensible Authentication Protocol EAP) Method Requirements for Wireless LANs.