It uses time expiration to limit the distance a packet can transmit.
why use hash tree instead of a one-way hash chain to authenticate values? The bad thing of one-way chain is that keys are dependent on each other. So I cannot use keys arbitrarily since it may expose other keys that haven't been used. With hash tree, I can use any of the keys in any order as long as it has not been used yet.
why can it expose the key in the same packet? It still depends on the expiration time of that key.
Reviewed by
yanbinl
as

- 2008-10-02 01:34:22
As mobile ad hoc network applications are deployed, security emerges as a central requirement. In this paper, we introduce the wormhole attack, a severe attack in ad hoc networks that is particularly challenging to defend against. The wormhole attack is possible even if the attacker has not compromised any hosts, and even if all communication provides authenticity and confidentiality. In the wormhole attack, an attacker records packets (or bits) at one location in the network, tunnels them (possibly selectively) to another location, and retransmits them there into the network. The wormhole attack can form a serious threat in wireless networks, especially against many ad hoc network routing protocols and location-based wireless security systems. For example, most existing ad hoc network routing protocols, without some mechanism to defend against the wormhole attack, would be unable to find routes longer than one or two hops, severely disrupting communication. We present a general mechanism, called packet leashes, for detecting and, thus defending against wormhole attacks, and we present a specific protocol, called TIK, that implements leashes. We also discuss topology-based wormhole detection, and show that it is impossible for these approaches to detect some wormhole topologies.