1. Integrating Quality of Protection into Ad Hoc Routing Protocols Seung Yi, Prasad Naldurg, Robin Kravets University of Illinois at Urbana-Champaign

2. Traditional ad hoc routing protocols  Cooperative by nature  Rely on implicit trust-your-neighbor relationships  Focus on convergence time and routing performance, rather than security

3. Motivation

4. Security-Aware ad hoc Routing (SAR)  SAR is an approach to routing that incorporates security levels of nodes into traditional routing metrics  SAR is typically added on top of existing routing algorithms

5. Goals  Applications can specify the quality of protection on their ad hoc route with respect to security attributes relevant to them  SAR aims to protect routing control messages For example, disclose routing information to trusted nodes only

6. Routing Protocol  Assume the base protocol is on-demand, such as DSR  Source broadcasts a Route Request (RREQ) with desired quality of protection  Neighbors propagate RREQ only if they could support the specified quality of protection  RREQ sets up reverse path as it propagates  Destination sends Route Reply (RREP) once it receives RREQ

7. Path Establishment SD RREQ RREP

8. Security Attributes (1) AttributesTechniquesAttacks TimelinessTime stampsReplay OrderingSequence numbersReplay AuthenticityPasswords, certificates Impersonation AuthorizationCredentials

9. Security Attributes (2) AttributesTechniquesAttacks IntegrityDigests, digital signatures Modification, fabrication Non-repudiationChaining of digital signatures Repudiation ConfidentialityEncryptionEavedropping

10. Quality of Protection  We have seen how quality of protection is used in path establishment  How to specify quality of protection? Trust hierarchy Bit vector  One bit for each security attribute

11. Trust Hierarchy  Each level has predefined quality of protection  These levels represent the security capability of the mobile nodes and also of the paths  Associate a number with each level  Trust level or protection should be immutable Keys of each level are distributed to nodes on that level. Encrypt the portion of the RREQ and RREP headers that contain the trust level

12. Simulation Set-up  ns2 network simulator  50 mobile nodes and 3 trust levels 15 (H), 15 (M), 20 (L)  2 different traffic patterns with 20 flows 10% (H), 20% (M), 70% (L) 33% (H), 33% (M), 34% (L)  SAR is implemented on top of AODV

13. Path Discovery Traffic 1Traffic 2  SAR discovered fewer paths  Paths guaranteed to obey the security requirement

14. Routing Traffic Traffic 1Traffic 2  SAR has lower routing traffic overhead  nodes drop routing messages if they can not satisfy the security requirement

15. Simulation Time Traffic 1Traffic 2  SAR takes more time to finish  Data packets may follow longer but more secure paths  Control packets experience processing overhead

16. Strong Points  Exposes security levels to applications so that applications can adapt its behavior  Concept is simple and effective

17. Weak Points  Overhead: Encryption, hashes, …  If the ad hoc network does not have a path with nodes that meet RREQ’s security requirements, SAR may fail to find a route even if the network is connected

18. Open Questions  How does SAR perform in real-world experiments?  Which base protocols are most suitable for SAR?

19. Any Questions?