ITIS 6010/8010 Wireless Network Security Dr. Weichao Wang

2 Introduction Security issues –Routing protocols in mobile ad hoc networks Proactive routing Reactive routing Hybrid routing Location based routing –Issues Fake routing information Fake route updates and errors Location privacy

3 Introduction Securing sensor networks –Secure localization Wormhole attack, Sybil attack –Key establishment and management –Data aggregation/authorization –Clock synchronization

4 Introduction Key distribution and management –Key pre-distribution method –Authenticating public keys in sensor networks –Stateless and self-healing key distribution

5 Localization and its security –Range free localization –Neighbor relation verification –Location privacy –Location assisted security protocols

6 Intrusion detection in wireless networks –Packet sink –Attack pattern/User behavior collection –Evidence collection and distribution

7 Deny-of-service attacks –Signal level, MAC level and application level –Difference in available resource –Security operations: decryption and authentication

8 RFID and its security –Authenticating reader –Varying identity –Low probability of detection –Hiding in the crowd

9 Secure group communication –Multicast group formation –Secure inter-group communication –Key distribution and update

10 Energy aware security protocols –Routing –Multicast

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12 Mobile ad hoc networks –First described by IEEE standard –A set of nodes communicate in a self- organized manner (without infrastructure) –Easy to deploy and form –Adapt to topology and membership changes –Peer-to-peer, multi-hop wireless environments –Every node serves as router: store and forward

13 Characteristics of ad hoc networks –Dynamic topology and membership –Limited physical security –Energy constrained –Storage (not any more), processing, communication constrained Applications –Military operations –Collaborative data exchange –Emergency responses (fire safety/rescue/natural disaster)

14 Local network topology discovery –Neighbor discovery –Medium access control protocol Routing in ad hoc networks –Properly respond to route failure/changes –Route packets with minimum costs –Satisfy delay/throughput requirements

15 Requirements to routing protocols –Distributed, localized algorithm –Broken routes can be detected, fixed, or replaced in a timely manner –Reduce broadcast and route maintenance overhead Classification of routing protocols –Proactive –Reactive –Hybrid –Location based routing

16 DSDV (Destination sequenced distance vector) –A proactive protocol –Each node maintains its own routing table –Very similar to RIP for Internet –Using sequence numbers to prevent routing loops

17 Every routing table entry includes –Destination address –Metric (delay, hop, etc) –Next hop –Sequence number of the destination

18 How routes to node i are established? –It broadcasts a route update packet with path length one –The neighbors increment the path length by one and rebroadcast –The update packets are kept locally for a while to avoid repeated broadcasting –Merging the broadcast packets to reduce control overhead Routing table changes –Periodical full dump of the routing table –Incremental changes caused by route broken or other significant changes

19 Using sequence number to prevent loop –A node increments its sequence number to label the most recent routes. Only even sequence numbers are used. –A fresh route with the largest sequence is always preferred –With the same sequence, the shortest path is preferred

20 Respond to route broken –A broken link can be detected by the node –The metric of a broken link is set to infinity, sequence number incremented –All routes using this link as the next hop will be set to infinity, sequence number incremented –This information will propagate since it has a larger sequence number –It is difficult to enable local repair