Muhammad Mahmudul Islam Ronald Pose Carlo Kopp School of Computer Science & Software Engineering Monash University Australia

 Problem statement  Limitations of WEP and i  Features of Link Layer Security Protocol (LLSP)  Overview of LLSP  Security analysis of LLSP  Overhead of LLSP  Future work  Questions

What is Security  Authentications, verifies the authenticity of the sender  Encryption, hides information  Integrity, prevents unauthorized modification Security in ad-hoc networks above link layer  Secure route discovery and route maintenance (e.g. SAR, ARIADNE, ARAN etc)  Secure communication on end-to-end basis (e.g. IPSec)  Monitor traffic pattern and take necessary steps to minimize malicious/selfish behaviors (e.g. Watchdog, Pathrater, CONFIDANT etc) Common assumption of these solutions  A secured layer has already been deployed that securely distributes various keys, certificates and update information Link Layer Security Protocol (LLSP) is a solution for the underlying secured layer

WEP  Lacks dynamic key management  One way handshaking, reusing keys and the weaknesses of RC4 make WEP vulnerable to MITM attacks  Vulnerable to DoS attacks since association and dissociation messages are not authenticated  Not designed for multi-hop ad-hoc networks i  Requires a trusted third party authentication server (RADIUS) for authenticating new nodes  Uses symmetric keys for authenticating new nodes and exchanging session keys  Not designed for multi-hop ad-hoc networks

 Uses capability to flexibly represent the access right and the identification of each link  Authenticate and encrypt every packet for each link  Guarantee the integrity of information.  Dynamic key management  Reduces replay, MITM and DoS attacks  Not dependent on any trusted third party authentication server  Does not require any MAC-IP binding  Does not need synchronized clocks  Independent of any routing protocol  No network wide flooding of any information  Scales properly with changes in network topology  Does not suffer from initial setup delay for each session  Specially designed for SAHN-like networks

 Multi-hop ad-hoc network  Ideal for cooperative nodes, e.g. connecting houses and business  Topology is quasi-static  Uses wireless technology  Multi-hop QoS routing  Decentralized  Multi Mbps broadband service  No charges for SAHN traffic  Can run alongside TCP/IP  Conceived by Ronald Pose & Carlo Kopp in 1997 at Monash University, Australia

Security Services Provided by LLSP  Type 1: Authenticates a new node  Type 2: Updates the capability (CAP) of a link  Type 3: Updates the shared key (SHK) of a link  Type 4: Authenticates received packets and  Type 5: Encrypts payload of MAC layer

Authenticate a New Node

Update SHK

Update CAP

Secure and Authenticate Data packets

Various Packet Formats of LLSP

 CAP of a link as a certificate  Encrypting CAP & SIG ensure the authenticity of each packet  SIG ensures integrity  Encrypting SIG and SEQ reduces replay attacks  Updating keys and CAP regularly makes guessing or recomputing difficult by unauthorized nodes  DoS attacks by flooding is not propagated, i.e. kept confined within the neighborhood of the malicious node

Authentication Type Transmission Rate (Mbps) Total Duration (ms) Type Type 2, Type Type 4, Type 5 Any In real-time using AES HW Duration of authentication processes with b and HW supported AES

Communication Overhead for single pair of node (1/2)

Communication Overhead for single pair of node (2/2)

Communication Overhead for 35 pairs of node (1/2)

Communication Overhead for 35 pairs of node (2/2)

Enhance the effectiveness and robustness of LLSP by integrating a monitoring system that can detect malicious/selfish activities of other nodes Integrate LLSP with channel access mechanisms of other wireless technologies (e.g. IEEE e, ) and measure performance