Evaluation of Anonymized ONS Queries

Electronic Product Code (EPC) is the basis of a pervasive infrastructure for the automatic identification of objects on supply chain applications (e.g., pharmaceutical or military applications). This infrastructure relies on the use of the (1) Radio Frequency Identification (RFID) technology to tag objects in motion and (2) distributed services providing information about objects via the Internet. A lookup service, called the Object Name Service (ONS) and based on the use of the Domain Name System (DNS), can be publicly accessed by EPC applications looking for information associated with tagged objects. Privacy issues may affect corporate infrastructures based on EPC technologies if their lookup service is not properly protected. A possible solution to mitigate these issues is the use of online anonymity. We present an evaluation experiment that compares the of use of Tor (The second generation Onion Router) on a global ONS/DNS setup, with respect to benefits, limitations, and latency.Comment: 14 page

Systematizing Decentralization and Privacy: Lessons from 15 Years of Research and Deployments

Decentralized systems are a subset of distributed systems where multiple authorities control different components and no authority is fully trusted by all. This implies that any component in a decentralized system is potentially adversarial. We revise fifteen years of research on decentralization and privacy, and provide an overview of key systems, as well as key insights for designers of future systems. We show that decentralized designs can enhance privacy, integrity, and availability but also require careful trade-offs in terms of system complexity, properties provided, and degree of decentralization. These trade-offs need to be understood and navigated by designers. We argue that a combination of insights from cryptography, distributed systems, and mechanism design, aligned with the development of adequate incentives, are necessary to build scalable and successful privacy-preserving decentralized systems

Privacy preservation using spherical chord

Structured overlay networks are primarily used in data storage and data lookup, but they are vulnerable against many kinds of attacks. Within the realm of security, overlay networks have demonstrated applicability in providing privacy, availability, integrity, along with scalability. The thesis first analyses the Chord and the SALSA protocols which are organized in structured overlays to provide data with a certain degree of privacy, and then defines a new protocol called Spherical Chord which provides data lookup with privacy, while also being scalable, and addresses critical existing weaknesses in Chord and SALSA protocols. Spherical Chord is a variant of the Chord, and utilizes the concept of distributed hash table (DHT). Chord sends packets uni-directionally over a virtual id space in the overlay. While this feature provides lower latencies, it can be used by attackers to misroute and drop packets. Spherical Chord protocol introduces additional connections in the structured overlay and increases the path length and the number of paths for sending messages, hence making it more resilient to routing attacks. A new protocol focusing for constructing the Spherical Chord, followed by a new lookup protocol is defined in this thesis. The protocols are analyzed and it is demonstrated using both theoretical analysis and simulations that improved path availability helps in maintaining privacy, while also limiting the impact of routing attacks. --Abstract, page iii

MIX-crowds, an anonymity scheme for file retrieval systems

In this paper, we propose an anonymous scheme for file retrieval systems, MIX-Crowds, in which it is harder for an attacker to identify the requester of the file by making use of the idea of MIX [7] and Crowds [20] to establish a path from the requester to the file holder. Result shows that predecessor attack [26] is much more difficult to succeed compared with Crowds [20]. We are able to reduce the estimated number of rounds needed for successful predecessor attack for MIX-Crowds. We also propose a file transfer strategy according to file size. With such strategy, requests for small size files can be completed faster while the downloading time of large size files only increases slightly. © 2009 IEEE.published_or_final_versionThe 28th International Conference on Computer Communications (IEEE INFOCOM 2009), Rio de Janeiro, Brazil, 19-25 April 2009. In Proceedings of the IEEE Infocom, 2009, p. 1170-117

Cryptanalysis of a fair anonymity for the tor network

The aim of this paper is to present an attack upon the protocol of Diaz et al. \cite{Diaz}, which goal is to introduce a fair anonymity in the Tor network. This attack allows an attacker to impersonate Tor users with the complicity of an exit node

SOS: An Architecture for Mitigating DDoS Attacks

We propose an architecture called secure overlay services (SOS) that proactively prevents denial of service (DoS) attacks, including distributed (DDoS) attacks; it is geared toward supporting emergency services, or similar types of communication. The architecture uses a combination of secure overlay tunneling, routing via consistent hashing, and filtering. We reduce the probability of successful attacks by: 1) performing intensive filtering near protected network edges, pushing the attack point perimeter into the core of the network, where high-speed routers can handle the volume of attack traffic and 2) introducing randomness and anonymity into the forwarding architecture, making it difficult for an attacker to target nodes along the path to a specific SOS-protected destination. Using simple analytical models, we evaluate the likelihood that an attacker can successfully launch a DoS attack against an SOS-protected network. Our analysis demonstrates that such an architecture reduces the likelihood of a successful attack to minuscule levels. Our performance measurements using a prototype implementation indicate an increase in end-to-end latency by a factor of two for the general case, and an average heal time of less than 10 s

Information Slicing: Anonymity Using Unreliable Overlays

This paper proposes a new approach to anonymous communication called information slicing. Typically, anonymizers use onion routing, where a message is encrypted in layers with the public keys of the nodes along the path. Instead, our approach scrambles the message, divides it into pieces, and sends the pieces along disjoint paths. We show that information slicing addresses message confidentiality as well as source and destination anonymity. Surprisingly, it does not need any public key cryptography. Further, our approach naturally addresses the problem of node failures. These characteristics make it a good fit for use over dynamic peer-to-peer overlays. We evaluate the anonymity ofinformation slicing via analysis and simulations. Our prototype implementation on PlanetLab shows that it achieves higher throughput than onion routing and effectively copes with node churn

A revocable anonymity in Tor

This new protocol is based on the idea of introducing a revocable anonymity in Tor, which was presented in our recent paper entitled Another Tor is possible . Compared to that previous paper, this present scheme simplify the first protocol and reduce the power of the directory server, while maintaining the ability for the Tor community, to break the anonymity of a sender in case of misconduct. We also take the opportunity of this paper, to appeal the majors internet companies, to help in the creation of a responsible Tor network (without pedophiles, spies, ....), by mixing billions of data flowing through their networks with those of Tor

Another Tor is possible

The aim of this paper is to introduce some modifications in Tor, in order to improve user’s anonymity and relay’s security. Thus, we introduced a system that will ensure anonymity for all users, while maintaining the ability to break the anonymity of a sender in case of misconduct. The revocation of the anonymity will require the use of secret sharing schemes, since we assume that, the lifting of the anonymity of the dishonest user should not depend on a single entity, but on a consensus within the network. In addition to the revocation of the anonymity, we propose in this paper further improvements such as mixing Tor traffic with those of the major internet groups, using the camouflage, or introducing a honeypot in the network