ITIS 60108010 Wireless Network Security Dr Weichao Wang

ITIS 6010/8010 Wireless Network Security Dr. Weichao Wang

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 2

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

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

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

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

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

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

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

• Energy aware security protocols – Routing – Multicast 10

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Mobile ad hoc networks • Mobile ad hoc networks – First described by IEEE 802. 11 standard – A set of nodes communicate in a selforganized 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 12

• 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) 13

• 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 14

• 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 15

• 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 16

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

• 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 18

• 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 19

• 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 20