temporal key integrity protocol (802.11) (TKIP)

To improve WLAN security in 802.11 networks, the Wireless Ethernet Compatibility Alliance(WECA) has developed the Temporal Key Integrity Protocol (TKIP) to replace the WEP protocol. Like Wired Equivalent Privacy (WEP), TKIP uses the RC4 algorithm for encryption and employs Fast Packet Keying( FPK).

With the TKIP protocol, the key changes temporarily - hence the name of the protocol - whenever a data packet of 10 KB has been transmitted. The initialization vector( IV) consists of a Lo part of 16 bits and a Hi part of 32 bits. The length of the Lo part increases by one bit from data packet to data packet. The receiverchecks this sequence and discards data packets that have an initialization vector that has already been used. Since the MAC address of the sender is also mixed in, this ensures that the same initialization vector results in different RC4 keys for different senders. Furthermore, the TKIP protocol uses an additional hash value in addition to the Cyclic Redundancy Checksum(CRC) as a checksum with the Message Integrity Check( MIC).

The Temporal Key Integrity Protocol (TKIP) is a specification from IEEE and is used in the WiFi Protected Architecture(WPA) and in 802.11i.