A Lightweight Hop-by-Hop Authentication Protocol For Ad-Hoc Networks

Speaker: Hsien-Pang Tsai

Teacher: Kai-Wei Ke

Date: 2005/01/20

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Outline

Introduction LHAP Security Analysis Performance Analysis Conclusion

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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.

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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.

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Public Key Algorithm (cont.)

Public Key Encryption

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Public Key Algorithm (cont.)

Public Key authentication

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Outline

Introduction LHAP Security Analysis Performance Analysis Conclusion

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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.

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Notation

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Trust Management

Trust Bootstrapping

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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.

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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.

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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.

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Outline

Introduction LHAP Security Analysis Performance Analysis Conclusion

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Security Analysis

Outside attacks Single outside attack Collaborative outside attack Hidden terminal attack

Inside attacks Single inside attack Insider clone attack

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Outside Attacks

Single outside attack

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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.

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Outside Attacks (2)

Hidden terminal attack IEEE 802.11 solves the problem using CSMA/CA

with ACKs and optional RTS/CTS control packet.

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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).

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Outline

Introduction LHAP Security Analysis Performance Analysis Conclusion

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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,…

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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.

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Outline

Introduction LHAP Security Analysis Performance Analysis Conclusion

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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.

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Reference

1. Sencun Zhu, and Shouhuai Xu, “LHAP:A lightweight Hop-by-Hop Authentication Protocol For Ad-Hoc Networks”, ICDCSW’03, IEEE 2003.

2. Adrian Perrig, and Ran Canetti, “Efficient Authentication and Signing of Multicast Streams over Lossy Channels”, IEEE 2000.