Wireless Unification Theory

Wireless Unification Wireless Unification TheoryTheory

William ArbaughWilliam Arbaugh

University of MarylandUniversity of Maryland

College ParkCollege Park

BureaucracyBureaucracy

Speakers please introduce yourself to me Speakers please introduce yourself to me and provide a copy of your slides to the and provide a copy of your slides to the note takernote taker

Workshop should be interactive- ask Workshop should be interactive- ask questions, answer questionsquestions, answer questions

What do you want from the What do you want from the Workshop?Workshop?

?

Welcome!Welcome!

Program consists of talks and discussionsProgram consists of talks and discussions Want to focus on discussions (more to Want to focus on discussions (more to

follow)follow) Goal is to identify hard research problems Goal is to identify hard research problems

and potential bureaucratic and and potential bureaucratic and standardization stumbling blocksstandardization stumbling blocks

Technical TrendsTechnical Trends

Wireless access is becoming ubiquitous and Wireless access is becoming ubiquitous and broadband in naturebroadband in nature

Users are become more mobileUsers are become more mobile Mobility for data access is changing from Mobility for data access is changing from

“discrete mobility” to “continous mobility”“discrete mobility” to “continous mobility” Base stations are cheaper with less physical Base stations are cheaper with less physical

securitysecurity All of the wireless technologies have differing All of the wireless technologies have differing

authentication and access control frameworks!authentication and access control frameworks! InterworkingInterworking

ThreatThreat

Interworking allows attackers to find the Interworking allows attackers to find the “path of least resistance” and establish “path of least resistance” and establish “man in the middle attacks”“man in the middle attacks” The network with the weakest security will be The network with the weakest security will be

the entry pointthe entry point Providers will either not allow networks Providers will either not allow networks

with weak security to join (limit with weak security to join (limit Interworking growth) or allow it which Interworking growth) or allow it which introduces security problems.introduces security problems.

Workshop GoalsWorkshop Goals

How do we tie these networks together in How do we tie these networks together in a secure fashion?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?

TechnicalTechnical

Patch work of technologyPatch work of technology

EAP

A5

PEAP

TLS

AES-CCM

CAVE

CHAP

AKA

HLR

VLR

Standardize it?Standardize it?

IRTFIETF

IEEE

WWRF

ISO

3GPP

How do we do it?How do we do it?

I have no idea!I have no idea! One of the main motivations for this One of the main motivations for this

workshop!workshop!

Things to think aboutThings to think about

What are the research questions?What are the research questions? What are the problems?What are the problems?

Standardization problemsStandardization problems Technical problemsTechnical problems Policy problemsPolicy problems

Technical OverviewTechnical Overview

IEEE 802.1xIEEE 802.1x EAPEAP RoamingRoaming

IEEE 802.1xIEEE 802.1x

Provides access control and key Provides access control and key distribution method to AP/base stationdistribution method to AP/base station

Centralized authenticationCentralized authentication Uses EAPUses EAP

Dual Port ModelDual Port Model

Controlled Port Uncontrolled Port

Authenticator System

Port unauthorized

Authentication Server

LAN

Access Point

AccessServer

Client / Supplicant

Trust RelationshipsTrust Relationships

Authentication Server

EAP method

Possibly viaRADIUS sharedsecret

Note: I am using trust here loosely since onlya security association is established.

Trust RelationshipsTrust Relationships

Authentication Server

EAP method

Possibly viaRADIUS sharedsecret

Note: I am using trust here loosely since onlya security association is established.

Transitively derived

Trust RelationshipsTrust Relationships

Note that the client and the AP/Base Note that the client and the AP/Base station have no direct trust relationshipstation have no direct trust relationship

It is derived transitively It is derived transitively if and only ifif and only if the the infrastructure establishes a trust relation infrastructure establishes a trust relation between the AP and the RADIUS serverbetween the AP and the RADIUS server

EAP SessionEAP Session

AuthenticationServer

Supplicant Authenticator

EAP REQUEST/IDENTITY

EAP RESPONSE/IDENTITY (MyID)

EAP REQUEST/OTP, OTP Challenge

EAP RESPONSE/OTP, OTP PW

EAP Success

Port authorized

EAP AuthenticationEAP Authentication

Authentication may not be mutualAuthentication may not be mutual Loss of anonymity due to identity requestLoss of anonymity due to identity request What are you authenticating?What are you authenticating?

User?User? Device?Device? Do we need both?Do we need both?

Roaming ChallengesRoaming Challenges

What is equivalent security?What is equivalent security? Hand-off’s between differing physical and Hand-off’s between differing physical and

MAC layers in under 30ms?MAC layers in under 30ms? Soft hand-over easy at layers 2 and below but Soft hand-over easy at layers 2 and below but

more difficult at layer 3 and abovemore difficult at layer 3 and above Hard hand-over just plain hardHard hand-over just plain hard

Some authentication methods are Some authentication methods are complex, compute intensive, and take too complex, compute intensive, and take too longlong

What did I miss?What did I miss?