AKA stands for the Authentication and Key Agreement. It is a security protocol used in 3G networks. AKA is also used for one-time password generation mechanism for Digest access authentication. AKA is a challenge-response based mechanism that uses symmetric cryptography.
AKA Authentication and Key Agreement a.k.a. 3G Authentication, Enhanced Subscriber Auth. (ESA)
The basis for the 3G authentication mechanism defined as a successor to CAVE-based Authentication. AKA provides procedures for mutual authentication of the MS and serving system. The successful execution of AKA results in the establishment of a security association (i.e., set of security data) between the MS and serving system that enables a set of security services to be provided.
Major advantages of AKA over CAVE-based authentication include:
- Larger authentication keys (128-bit )
- Stronger hash function (SHA-1)
- Support for mutual authentication
- Support for signaling message data integrity
- Support for signaling information encryption
- Support for user data encryption
- Protection from rogue MS when dealing with R-UIM
AKA is not yet implemented in CDMA2000 networks, although it is expected to be used for IMS. To ensure interoperability with current devices and partner networks, support for AKA in CDMA networks and handsets will likely be in addition to CAVE-based authentication.