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A Lightweight Hop-by-Hop Authentication Protocol For Ad-Hoc Networks. Speaker: Hsien-Pang Tsai Teacher: Kai-Wei Ke Date: 2005/01/20. Outline. Introduction LHAP Security Analysis Performance Analysis Conclusion. Securing Ad hoc Networks.
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A Lightweight Hop-by-Hop Authentication Protocol For Ad-Hoc Networks Speaker: Hsien-Pang Tsai Teacher: Kai-Wei Ke Date: 2005/01/20
Outline • Introduction • LHAP • Security Analysis • Performance Analysis • Conclusion
Securing Ad hoc Networks • Most ad hoc networks do not have any provisions for restricting or regulating the traffic. • Recently researchers have proposed security extensions for authenticating routing control packets. • A simple solution is to use a network-wide key shared by all nodes.
Public Key Algorithm • Two problems with shared-key: • Key management • Digital signatures (Authentication) • Key feature of public key cryptosystem • Two keys: Public Key & Private Key • Computational infeasible to determine decryption key.
Public Key Algorithm (cont.) • Public Key Encryption
Public Key Algorithm (cont.) • Public Key authentication
Outline • Introduction • LHAP • Security Analysis • Performance Analysis • Conclusion
LHAP • Lightweight hop-by-hop authentication. • A node joining an ad hoc network only needs to perform some inexpensive authentication with its neighbors. • Residing in between the data link layer and the network layer.
Trust Management • Trust Bootstrapping
Trust Management (1) • Trust Maintenance • Each node broadcasts an KEYUPDATE message (with TTL=1) to its neighbors. • The KEYUPDATE message is authenticated with the next TESLA key in its key chain. • Preventing malicious nodes from forging traffic using the TRAFFIC keys node A has already released.
Trust Management (2) • Trust Termination • When a compromised node is detected, all the node will terminate their trust relationship with that node permanently. • When a node doesn’t receive a valid KEYUPDATE message from a neighbor within a TESLA interval, it will terminate it trust of this neighbor temporarily.
Lightweight Traffic Authentication • Each node generates a one-way key chain used for traffic authentication. • Node A want to broadcast a packet M: • Benefit: • Enable instant verification of traffic packets. • It is not necessary to disclose TRAFFIC keys periodically.
Outline • Introduction • LHAP • Security Analysis • Performance Analysis • Conclusion
Security Analysis • Outside attacks • Single outside attack • Collaborative outside attack • Hidden terminal attack • Inside attacks • Single inside attack • Insider clone attack
Outside Attacks • Single outside attack
Outside Attacks (1) • Collaborative outside attack • Attacker P1 and P2 have a private channel. • P1 forwards every message it eavesdropped from node A, including KEYUPDATE messages and traffic packets. • Solution: • Allow a receiving node to determine if they should be able to hear each other.
Outside Attacks (2) • Hidden terminal attack • IEEE 802.11 solves the problem using CSMA/CA with ACKs and optional RTS/CTS control packet.
Insider Attacks • Single insider attack • A compromised node might attempt to flood the network with many traffic packets. • Insider clone attack • When a compromised nod shares its private key with its outside conspirators. • Solution • Instruction Detection System (IDS).
Outline • Introduction • LHAP • Security Analysis • Performance Analysis • Conclusion
Performance Analysis • Computational Overhead • RSA digital signature verifications. • Hash computation • Latency • A node verifies a traffic packet it receives by computing one or more hashes. • Traffic Byte Overhead • A node adds a traffic key to every traffic packet it sends,…
Performance Analysis (cont.) • JOIN message, a public key certificate and the size of a digital signature. • A node sends an ACK packet to every new neighbor… • KEYUPDATE message.
Outline • Introduction • LHAP • Security Analysis • Performance Analysis • Conclusion
Conclusion • Presented a lightweight hop-by-hop authentication protocol for network access control in ad hoc networks. • Transparent to and independent of the routing protocol.
Reference • Sencun Zhu, and Shouhuai Xu, “LHAP:A lightweight Hop-by-Hop Authentication Protocol For Ad-Hoc Networks”, ICDCSW’03, IEEE 2003. • Adrian Perrig, and Ran Canetti, “Efficient Authentication and Signing of Multicast Streams over Lossy Channels”, IEEE 2000.