An Improvement to Trust Based Cross-Layer Security Protocol against Sybil Attacks (DAS)

摘要

The performance of distributed networks depends on collaboration among distributed entities. To enhance security in distributed networks, such as ad hoc networks, it is important to evaluate the trustworthiness of participating entities since trust is the major driving force for collaboration. The trust based security protocol based on a cross-layer approach attains confidentiality and authentication of packets in both routing and link layers of MANETs but it doesn’t address few attacks like Bad Mouthing Attack, On-off Attack, and Conflicting Behavior Attack, Sybil Attack and Newcomer Attack. In this paper we present DAS, a protocol for reducing of the corruptive/malicious influences of Sybil attacks. Malicious users in general may create multiple identities with few trust relationships. Hence there is a disproportionately small gap in the graph between the Sybil nodes and the honest nodes. DAS exploits this property so as to bind the number of identities a malicious user can create. We simulate the effectiveness of DAS both analytically and experimentally.