Paper 2017/253
A Modular Security Analysis of EAP and IEEE 802.11
Chris Brzuska and Håkon Jacobsen
Abstract
We conduct a reduction-based security analysis of the Extensible Authentication Protocol (EAP), a widely used three-party authentication framework. EAP is often found in enterprise networks where it allows a client and an authenticator to establish a shared key with the help of a mutually trusted server. Considered as a three-party authenticated key exchange protocol, we show that the general EAP construction achieves a security notion we call 3P-AKE$^w$. %under the assumption that it employs \emph{channel binding}. %Channel binding ensures that the session key derived by the client and the authenticator is cryptographically bound to them. The 3P-AKE$^w$ security notion captures the idea of \emph{weak forward secrecy} and is a simplified three-party version of the well-known eCK model in the two-pass variant. Our analysis is modular and reflects the compositional nature of EAP. Additionally, we show that the security of EAP can easily be upgraded to provide \emph{full} forward secrecy simply by adding a subsequent key-confirmation step between the client and the authenticator. In practice this key-confirmation step is often carried out in the form of a 2P-AKE protocol which uses EAP to bootstrap its authentication. A concrete example is the extremely common IEEE~802.11 protocol used in WLANs. In enterprise settings EAP is often used in conjunction with IEEE~802.11 in order to allow the wireless client to authenticate itself to a wireless access point (the authenticator) through some centrally administrated server. Building on our modular results for EAP, we get as our second major result the first reduction-based security result for IEEE~802.11 combined with EAP.
Metadata
- Available format(s)
- Category
- Cryptographic protocols
- Publication info
- A major revision of an IACR publication in PKC 2017
- Keywords
- 3P-AKE2P-AKEEAP802.11partner functions
- Contact author(s)
- hakoja @ item ntnu no
- History
- 2017-03-21: revised
- 2017-03-20: received
- See all versions
- Short URL
- https://ia.cr/2017/253
- License
-
CC BY