Modern low-latency anonymity systems, no matter whether constructed as an overlay or implemented at the network layer, offer limited security guarantees against traffic analysis. On the other hand, high-latency anonymity systems offer strong security guarantees at the cost of computational overhead and long delays, which are excessive for interactive applications. We propose TARANET, an anonymity system that implements protection against traffic analysis at the network layer, and limits the incurred latency and overhead. In TARANET's setup phase, traffic analysis is thwarted by mixing. In the data transmission phase, end hosts and ASes coordinate to shape traffic into constant-rate transmission using packet splitting. Our prototype implementation shows that TARANET can forward anonymous traffic at over 50 Gbps using commodity hardware.
The first class of network-layer anonymity protocols proposed is the so-called system, which consists of two proposals, @cite_50 and @cite_43 . These systems defend against topological attacks by encrypting forwarding information in packet headers. However, in both schemes, packets stay unchanged from hop to hop, thus enabling bit-pattern correlation of packets at distinct compromised nodes.
@cite_43 @cite_50
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The ability to locate random relays is a key challenge for peer-to-peer (P2P) anonymous communication systems. Earlier attempts like Salsa and AP3 used distributes hash table lookups to locate relays, but the lack of anonymity in their lookup mechanisms enables an adversary to infer the path structure and compromise used anonymity. NISAN and Torsk are state-of-the-art systems for P2P anonymous communication. Their designs include mechanisms that are specifically tailored to mitigate information leak attacks. NISAN proposes to add anonymity into the lookup mechanism itself, while Torsk proposes the use of secret buddy nodes to anonymize the lookup initiator. In this paper, we attack the key mechanisms that hide the relationship between a lookup initiator and its selected relays in NISAN and Torsk. We present passive attacks on the NISAN lookup and show that it is not as anonymous as previously thought. We analyze three circuit construction mechanisms for anonymous communication using the NISAN lookup, and show that the information leaks in the NISAN lookup lead to a significant reduction in user anonymity. We also propose active attacks on Torsk that defeat its secret buddy mechanism and consequently compromise user anonymity. Our results are backed up by probabilistic modeling and extensive simulations. Our study motivates the search for a DHT lookup mechanism that is both secure and anonymous. Popular anonymous communication systems often require sending packets through a sequence of relays on dilated paths for strong anonymity protection. As a result, increased end-to-end latency renders such systems inadequate for the majority of Internet users who seek an intermediate level of anonymity protection while using latency-sensitive applications, such as Web applications. This paper serves to bridge the gap between communication systems that provide strong anonymity protection but with intolerable latency and non-anonymous communication systems by considering a new design space for the setting. More specifically, we explore how to achieve near-optimal latency while achieving an intermediate level of anonymity with a weaker yet practical adversary model (i.e., protecting an end-host's identity and location from servers) such that users can choose between the level of anonymity and usability. We propose Lightweight Anonymity and Privacy (LAP), an efficient network-based solution featuring lightweight path establishment and stateless communication, by concealing an end-host's topological location to enhance anonymity against remote tracking. To show practicality, we demonstrate that LAP can work on top of the current Internet and proposed future Internet architectures.