Wireless Unification Theory William Arbaugh University of Maryland College Park

Bureaucracy  Speakers please introduce yourself to me and provide a copy of your slides to the note taker  Workshop should be interactive- ask questions, answer questions

What do you want from the Workshop? ?

Welcome!  Program consists of talks and discussions  Want to focus on discussions (more to follow)  Goal is to identify hard research problems and potential bureaucratic and standardization stumbling blocks

Technical Trends  Wireless access is becoming ubiquitous and broadband in nature  Users are become more mobile  Mobility for data access is changing from “discrete mobility” to “continous mobility”  Base stations are cheaper with less physical security  All of the wireless technologies have differing authentication and access control frameworks!  Interworking

Threat  Interworking allows attackers to find the “path of least resistance” and establish “man in the middle attacks” The network with the weakest security will be the entry point The network with the weakest security will be the entry point  Providers will either not allow networks with weak security to join (limit Interworking growth) or allow it which introduces security problems.

Workshop Goals  How do we tie these networks together in a secure fashion? Deal with legacy networks? Deal with legacy networks? Deal with future networks? Deal with future networks? Vertical/Horizontal roaming? Vertical/Horizontal roaming?

Technical  Patch work of technology EAP A5 PEAP TLS AES-CCM CAVE CHAP AKA HLR VLR

Standardize it? IRTF IETF IEEE WWRF ISO 3GPP

How do we do it?  I have no idea!  One of the main motivations for this workshop!

Things to think about  What are the research questions?  What are the problems? Standardization problems Standardization problems Technical problems Technical problems Policy problems Policy problems

Technical Overview  IEEE 802.1x  EAP  Roaming

IEEE 802.1x  Provides access control and key distribution method to AP/base station  Centralized authentication  Uses EAP

Dual Port Model Controlled PortUncontrolled Port Authenticator System Port unauthorized LAN Access Point Access Server Client / Supplicant

Trust Relationships EAP method Possibly via RADIUS shared secret Note: I am using trust here loosely since only a security association is established.

Trust Relationships EAP method Possibly via RADIUS shared secret Note: I am using trust here loosely since only a security association is established. Transitively derived

Trust Relationships  Note that the client and the AP/Base station have no direct trust relationship  It is derived transitively if and only if the infrastructure establishes a trust relation between the AP and the RADIUS server

EAP Session Authentication Server SupplicantAuthenticator EAP REQUEST/IDENTITY EAP RESPONSE/IDENTITY (MyID) EAP REQUEST/OTP, OTP Challenge EAP RESPONSE/OTP, OTP PW EAP Success Port authorized

EAP Authentication  Authentication may not be mutual  Loss of anonymity due to identity request  What are you authenticating? User? User? Device? Device? Do we need both? Do we need both?

Roaming Challenges  What is equivalent security?  Hand-off’s between differing physical and MAC layers in under 30ms? Soft hand-over easy at layers 2 and below but more difficult at layer 3 and above Soft hand-over easy at layers 2 and below but more difficult at layer 3 and above Hard hand-over just plain hard Hard hand-over just plain hard  Some authentication methods are complex, compute intensive, and take too long

What did I miss?