An Efficient Overlay Infrastructure for Privacy-Preserving Communication on the Internet

Jalal Al-Muhtadi
2007 Journal of King Saud University: Computer and Information Sciences  
This paper presents Mist2 (Mist 2nd generation), an overlay infrastructure for privacy-preserving communication. Nodes are arranged in concentric rings, which reduce average overlay hop latencies. Mist2 builds on the strengths of previous work on Mist, and significantly improves on the communication overhead, resilience to router failures, and the distributed nature of the algorithm. Mist2 provides sender, receiver, and sender-receiver anonymity for communicating end users. Compared to previous
more » ... approaches, Mist2 significantly improves the communication efficiency in latency without sacrificing the level of anonymity. This paper proposes an enhancement to the original Mist, and improves this solution using rings resulting in Mist2. The simulation results clearly demonstrate the improved performance of anonymous communication in Mist2 compared to relevant systems, while maintaining anonymity. Since the proposed ring-based approach optimizes path latencies, it performs better than the other proposed solutions where the overlay hops can potentially traverse large distances. 40 user anonymity include identity privacy which implies protecting the identity information about a user such as name, passwords, email addresses, telephone numbers, credit card numbers, private keys, geographic location, etc., from inadvertent exposure. In order to preserve the anonymity of a user, researchers have focused on different aspects of the problem. Specifically, they focus their attention on sender anonymity, receiver anonymity, and sender-receiver anonymity [1] . A system provides sender anonymity if and only if it is not possible for the recipient of a message to identify the original sender. In receiver anonymity, it is not possible to ascertain who the receiver of a particular message is, even though the receiver may be able to identify the sender. Sender-receiver anonymity is the combination of both properties. Some of the proposed solutions place implicit trust on the communication infrastructure [2, 3] , whereas in other solutions the infrastructure is oblivious to identity information of the endpoints of a communication [1, [4] [5] [6] [7] [8] . This section briefly reviews related research and situates this work in this context. One of the earliest efforts to provide anonymity was [8], where the focus was on hiding traffic patterns to foil traffic analysis using a technique called mixing. Routers communicate with each other using fixed length packets that are sent out at uniform intervals. Protocol messages are mixed in randomly with dummy packets to keep a constant flow of traffic in and out of the routers. In addition, all messages are encrypted with multiple router-specific keys by the sender of the message, who also picks the path the message follows through the network. The causality relationships between messages are not preserved. Onion routing implements this idea by forming an overlay network of Onion routers that do the mixing [6]. Encrypted layers are peeled off (like an onion) at each hop, hiding all routing information except the previous and next hop. Tor [9] is a second-generation Onion Routing system that addresses limitations in the original design by adding congestion control, directory servers, integrity checking, and other enhancements. These schemes provide anonymity to both the sender and receiver of the communication. Crowds [4] , on the other hand, is a solution that specifically targets anonymous web browsing. Crowd routers are dispersed across the Internet and communicate with each other using overlays forming a fully connected graph. Web requests from a sender are routed to a Crowds router and each Crowds router can decide to probabilistically forward them to another Crowds router or send it directly to the web server. If the request is forwarded, some state is stored on the router so that a reverse path is set up for the response from the server to the sender using a mechanism similar to virtual circuits. Using this protocol, the server only sees the IP address of the last Crowd router. The anonymity of the sender is preserved in this case because the originator of the message could equally likely be any one from the whole set of Crowds' users. While Crowds provides sender-anonymity, the overall path latencies are high, since the message can be routed across the Internet many times.
doi:10.1016/s1319-1578(07)80003-6 fatcat:brerlu7ezbaprbrt3hukco326y