Two Anonymous Cooperative Cache-Based Data Access Schemes in Mobile Ad Hoc Networks

Mobile ad hoc network has been extensively studied in recent years due to its potential applications in civilian and military environments. Cooperative caching, which allows the sharing and coordination of cached data among multiple nodes, could be employed to improve data accessibility and reduce data access cost in mobile ad hoc networks. In this paper, we give anonymity requirements for cooperative cache-based data access in mobile ad hoc networks and present two efficient anonymous data access schemes based on onion message and pseudonym-based encryption, respectively. The proposed schemes can not only protect confidentiality of sensitive cache data but can also protect privacy of nodes and routes. 1. Introduction A mobile adhoc network (MANET) is a self-configuring temporary network of mobile devices connected by wireless links without infrastructure support. The benefits of flexible routing, global connectivity and a highly adaptive potential make MANETs suitable for a wide range of applications in both military and commercial environments, such as battlefields, disaster relief operations, personal area networking, mobile information sharing, and vehicular networks. Similar to the wired network, security requirements for MANETs include availability, confidentiality, integrity, authentication, nonrepudiation. Compared to the wired network, MANET is more vulnerable to security attacks due to its features of open medium, dynamic changing topology, cooperative algorithms, lack of centralized monitoring and management point, and so forth [1]. Traffic analysis is one of the most serious security attacks in MANETs due to the broadcast nature of the wireless medium. In this attack, adversaries can obtain sensitive information about the applications even without revealing the contents of the messages just by observing network traffic pattern. For example, an attacker can identify the communicating parties and their positions by tracing and analyzing the network traffic patterns. This may lead to severe threats in security-sensitive applications. For instance, in a battle field the enemy can physically destroy the important mobile nodes if they can identify and locate such nodes by traffic analysis. Ideally, a node should be able to keep its identity, its location and its correspondents private, that is, remain anonymous. Simple traffic padding approach by generating dummy traffic into the network does not aim to hide the identifiers of communicating nodes and so cannot completely prevent traffic analysis. In order to thwart traffic analysis attack,