Key management

4.5.4.5 Key management

The enhanced data confidentiality, data authentication, and replay protection mechanisms require fresh
cryptographic keys and corresponding security associations. The procedures defined in this standard provide
fresh keys by means of protocols called the 4-Way Handshake, FT 4-Way Handshake, FT Protocol, FT
Resource Request Protocol, and Group Key Handshake.
4.5.4.6 Data origin authenticity
The data origin authenticity mechanism defines a means by which a STA that receives a data or protected
Robust Management frame can determine which STA transmitted the MAC protocol data unit (MPDU).
This feature is required in an RSNA to prevent one STA from masquerading as a different STA.
19Details of the ARC4 algorithm are available from RSA Security, Inc. Contact RSA Security, 174 Middlesex Turnpike, Bedford, MA
01730 (http://www.rsasecurity.com/), for algorithm details and the uniform ARC4 license terms that RSA offers to anyone wishing to
use ARC4 for the purpose of implementing the IEEE 802.11 WEP option. If necessary, contact the IEEE Standards Department
Intellectual Property Rights Administrator for details on how to communicate with RSA.

Data origin authenticity is only applicable to individually addressed data frames, and individually addressed
robust management frames. The protocols do not guarantee data origin authenticity for group addressed
frames, as this cannot be accomplished using symmetric keys and public key methods are too
computationally expensive.