684 GLOSSARYGMK Group master key. A cryptographic key used to derive a group transientkey (GTK) for the Temporal Key Integrity Protocol (TKIP) and AdvancedEncryption Standard (AES).greenfield network An original deployment of a telecommunications network.GRE tunnel A virtual link between two remote points on a network, created bymeans of the Generic Routing Encapsulation (GRE) tunneling protocol.GRE encapsulates packets within a transport protocol supported by thenetwork.GTK Group transient key. A cryptographic key used to encrypt broadcast andmulticast packets for transmissions using the Temporal Key IntegrityProtocol (TKIP) and Advanced Encryption Standard (AES).group master key See GMK.group transient key See GTK.H.323 A set of International Telecommunications Union TelecommunicationStandardization Sector (ITU-T) standards that define a framework forthe transmission of real-time voice signals over IP packet-switchednetworks.hash A one-way algorithm from whose output the input is computationallyinfeasible to determine. With a good hashing algorithm you canproduce identical output from two identical inputs, but finding twodifferent inputs that produce the same output is computationallyinfeasible. Hash functions are used widely in authentication algorithmsand for key derivation procedures.HiperLAN High-performance radio local area network. A set of wireless LAN(WLAN) communication standards used primarily in European countriesand adopted by the European Telecommunications Standards Institute(ETSI).HMAC Hashed message authentication code. A function, defined in RFC 2104,for keyed hashing for message authentication. HMAC is used withMD5 and the secure hash algorithm (SHA).hashed messageauthentication codeSee HMAC.
