An implementation of accountable anonymity

Complex well developed and established Anonymity systems lack Accountability. These systems offer unconditional anonymity to their users which can stimulate abusive behavior. Controlling abuse should be equally important as protecting the anonymity of legitimate users when designing anonymous applications. Current anonymity systems are promoted to family and friends, businesses, activists and the media. However, these same systems could potentially be used for: sending offensive email, spam, copyrighted material, cyber warfare, child pornography, pedophiles chatting with kids online or any other illegal activity performed on the Internet. Freedom of speech and the First Amendment allows people to express their opinions and choose any anonymity service and by no means will people be forced to use this system. In this thesis, a model that allows an anonymous yet accountable method of communication on the Internet is introduced. The design and implementation is based on a new proxy-re-encryption scheme and a modifed onion routing scheme. Techniques for Accountable Anonymity are demonstrated by building a lightweight prototype. In this system, users are registered in the system\u27s database in order to use it. In this research, the total network latency is signifcantly smaller when sending data over the network compared to The onion router (Tor) system which makes it deployable to use at a larger scale system. Also, the Accountable Anonymity system\u27s digital forensic mode makes it easier to track the perpetrators

A-MAKE: an efficient, anonymous and accountable authentication framework for WMNs

In this paper, we propose a framework, named as A-MAKE, which efficiently provides security, privacy, and accountability for communications in wireless mesh networks. More specifically, the framework provides an anonymous mutual authentication protocol whereby legitimate users can connect to network from anywhere without being identified or tracked. No single party (e.g., network operator) can violate the privacy of a user, which is provided in our framework in the strongest sense. Our framework utilizes group signatures, where the private key and the credentials of the users are generated through a secure three-party protocol. User accountability is implemented via user revocation protocol that can be executed by two semitrusted authorities, one of which is the network operator. The assumptions about the trust level of the network operator are relaxed. Our framework makes use of much more efficient signature generation and verification algorithms in terms of computation complexity than their counterparts in literature, where signature size is comparable to the shortest signatures proposed for similar purposes so far

Introducing Accountability to Anonymity Networks

Many anonymous communication (AC) networks rely on routing traffic through proxy nodes to obfuscate the originator of the traffic. Without an accountability mechanism, exit proxy nodes risk sanctions by law enforcement if users commit illegal actions through the AC network. We present BackRef, a generic mechanism for AC networks that provides practical repudiation for the proxy nodes by tracing back the selected outbound traffic to the predecessor node (but not in the forward direction) through a cryptographically verifiable chain. It also provides an option for full (or partial) traceability back to the entry node or even to the corresponding user when all intermediate nodes are cooperating. Moreover, to maintain a good balance between anonymity and accountability, the protocol incorporates whitelist directories at exit proxy nodes. BackRef offers improved deployability over the related work, and introduces a novel concept of pseudonymous signatures that may be of independent interest. We exemplify the utility of BackRef by integrating it into the onion routing (OR) protocol, and examine its deployability by considering several system-level aspects. We also present the security definitions for the BackRef system (namely, anonymity, backward traceability, no forward traceability, and no false accusation) and conduct a formal security analysis of the OR protocol with BackRef using ProVerif, an automated cryptographic protocol verifier, establishing the aforementioned security properties against a strong adversarial model

Anonymous reputation based reservations in e-commerce (AMNESIC)

Online reservation systems have grown over the last recent years to facilitate the purchase of goods and services. Generally, reservation systems require that customers provide some personal data to make a reservation effective. With this data, service providers can check the consumer history and decide if the user is trustable enough to get the reserve. Although the reputation of a user is a good metric to implement the access control of the system, providing personal and sensitive data to the system presents high privacy risks, since the interests of a user are totally known and tracked by an external entity. In this paper we design an anonymous reservation protocol that uses reputations to profile the users and control their access to the offered services, but at the same time it preserves their privacy not only from the seller but the service provider

Dining Cryptographers with 0.924 Verifiable Collision Resolution

The dining cryptographers protocol implements a multiple access channel in which senders and recipients are anonymous. A problem is that a malicious participant can disrupt communication by deliberately creating collisions. We propose a computationally secure dining cryptographers protocol with collision resolution that achieves a maximum stable throughput of 0.924 messages per round and which allows to easily detect disruptors.Comment: 11 pages, 3 figure

Lime: Data Lineage in the Malicious Environment

Intentional or unintentional leakage of confidential data is undoubtedly one of the most severe security threats that organizations face in the digital era. The threat now extends to our personal lives: a plethora of personal information is available to social networks and smartphone providers and is indirectly transferred to untrustworthy third party and fourth party applications. In this work, we present a generic data lineage framework LIME for data flow across multiple entities that take two characteristic, principal roles (i.e., owner and consumer). We define the exact security guarantees required by such a data lineage mechanism toward identification of a guilty entity, and identify the simplifying non repudiation and honesty assumptions. We then develop and analyze a novel accountable data transfer protocol between two entities within a malicious environment by building upon oblivious transfer, robust watermarking, and signature primitives. Finally, we perform an experimental evaluation to demonstrate the practicality of our protocol

The Anonymous Poster: How to Protect Internet Users’ Privacy and Prevent Abuse

The threat of anonymous Internet posting to individual privacy has been met with congressional and judicial indecisiveness. Part of the problem stems from the inherent conflict between punishing those who disrespect one\u27s privacy by placing a burden on the individual websites and continuing to support the Internet\u27s development. Additionally, assigning traditional tort liability is problematic as the defendant enjoys an expectation of privacy as well, creating difficulty in securing the necessary information to proceed with legal action. One solution to resolving invasion of privacy disputes involves a uniform identification verification program that ensures user confidentiality while promoting accountability for malicious behavior