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This paper introduces the MASK routing protocol for secure and anonymous communication in Mobile Ad Hoc Networks. Discussing mobile ad-hoc networks' military, civilian, and personal uses, the paper addresses security issues and proposes measures like LPI/LPD, traffic padding, and end-to-end encryption. The MASK protocol offers sender-receiver anonymity, untraceability, secure authentication, and low cryptographic overhead, resistant to various attacks. The system design involves dynamic node changes, pseudonyms for secure authentication, and anonymous neighborhood authentication between nodes. The protocol enhances network security by ensuring anonymous route discovery, data forwarding, and countering various attacks through message coding, flow recognition, and timing analysis. Performance evaluation shows advantages over traditional routing protocols, emphasizing benefits in heavy traffic scenarios.
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CSCE 715 Anonymous Communication in Mobile Ad Hoc Networks Vishal Patel
Introduction • What is Mobile Ad-hoc Network? • Also called as MANET • They became popular for research in mid – late 1990’s • Vehicular ad – hoc networks (VANETs)
Introduction • This paper proposes……. • Security • Traffic Analysis
Introduction • Military uses of MANETs • Civilian uses of MANETS • Personal Uses of MANETS
Security Issues/Countermeasures • MANETS ARE EASILY HACKABLE!!!! • Countermeasures • -LPI/LPD • -Traffic Padding • -End to End Encryption
MASK-Routing Protocol • An on-demand anonymous routing protocol for MANETS • Fulfills the routing task without disclosing real identity • --Anonymous neighborhood • --Anonymous route discovery
MASK is designed to meet • Sender, receiver anonymity • Untraceability and Unlocatability • Anonymous secure authentication • Low cryptographic overhead • Resistance to a wide range attacks
Preliminaries and Models • Let G1 and G2 be two groups of the same prime order q • G1 – additive group and G2 – multiplicative group • Paring is a computable bilinear map where f : G1XG1 G2
Adversarial Model • Active attacks • -Visible attack (radio jamming, DoS) • Countermeasures to active attacks • -IDS, frequency hopping
Adversarial Model • Passive Attacks • - Invisible attack (Eavesdropping, inject packets) • Countermeasures • - LPI/LPD, spread spectrum
Network Model • Limited transmission • Non-neighboring nodes must communicate via multi-hop • Wireless links are unreliable • MAC interface in promiscuous mode
MASK System Design • Nodes changes vigorously. • H1 z;{0,1}* G1 • H2 : {0,1}* {0,1}β • PSi = collision resistant pseudonyms • Si = secret point set • Given one pseudonym and secret pair cannot deduce the master key
Anonymous Neighborhood Authentication • Ensure two neighboring nodes have trust relationship • The nodes create there own key
Alice wants to send a message to Bob A random pseudonym is picked from their set A session key from bob and secret point set is calculated to send the message Example (Alice & Bob)
Example continued • The message is send to Alice • After Alice’s receives a reply, she then calculates her session key and authenticates Bob based on his authenticator • She then send the message same way bob replied • And now we have anonymous authentication
Example continued • After authentication, they can compute how many pairs of session key can be used • With the same process, Alice knows all her neighbors and will create a table which will have session key and link identifier • The link ID will be used to identify the packets transmitted between Alice and Bob • When all pairs have been used, they need to generate another set of pairs
Example Continued • Only Trusted Authority and give pseudonym to a node, the hacker does not learn anything • The hacker (Trudy) cannot compute the link identifier or the shared key
Anonymous Route Discovery • Neighbors authenticate and establish session key and link ID pairs • Each node has • Forwarding routing table <dest_id, destSeq, pre-link, next-link> • Reverse route table <dest_id, destSeq, pre-hop-pseudonym> • Target link table
Anonymous Route Request • ARREQ • Packet format of <ARREQ, ARREQ_id, dest_id, destSeq, PSx> • Intermediate node C received ARREQ • Rebroadcasts ARREQ • Previously seen ARREQ_ids are discarded • Continues until all nodes have broadcast
Random routes MASK doesn’t use best path, which could delay the packet Anonymous route are used so the nodes inform the network to remove the path that was taken Anonymous Data Forwarding
Attacks against MASK • Message Coding Attack • -- attack happens when contents are not changed during transmissions • Countermeasures • Random padding • Per-hop link encryption
Flow Recognition and Message Replay Attacks • Recognize packets that belong to same ongoing communication • Countermeasures • Multipath packet forwarding • LinkIDs should be change periodically
Timing Analysis Attack • Attacker learns what time packets come in/out • Countermeasures • Forge a packet with fake LINKID • Wait random amount of time
Performance Evaluation • Cryptographic Operations • -Anonymous Neighborhood Authentication • -Hop-by-Hop link encryption/decryption
Performance • Routing performance • -MASK v/s AODV • Three metrics used • -Packet Delivery Ratio • -Average end-to-end delay of data packets • -Normalized routing load
PDR v/s MASK • Normal load – 20 sources • -No difference • Large load – 40 sources • -MASK is advantageous
PDR v/s MASK Cont. • Same as Packet delivery ratio • Finds long path less frequently
PDR v/s MASK Cont. • Normal traffic • -AODV is better • Heavy traffic • -MASK is better • MAC layer collisions
Conclusion • Anonymity • Unlocatability • Untraceability • Can immune to wide range of attacks • Comparable routing performance
