Authentication over Noisy Channels

In this work, message authentication over noisy channels is studied. The model developed in this paper is the authentication theory counterpart of Wyner's wiretap channel model. Two types of opponent attacks, namely impersonation attacks and substitution attacks, are investigated for both single message and multiple message authentication scenarios. For each scenario, information theoretic lower and upper bounds on the opponent's success probability are derived. Remarkably, in both scenarios, lower and upper bounds are shown to match, and hence the fundamental limit of message authentication over noisy channels is fully characterized. The opponent's success probability is further shown to be smaller than that derived in the classic authentication model in which the channel is assumed to be noiseless. These results rely on a proposed novel authentication scheme in which key information is used to provide simultaneous protection again both types of attacks.Comment: Appeared in the Proceedings of the 45th Annual Allerton Conference on Communication, Control and Computing, Monticello, IL, September 26 - 28, 200

The MAGIC Mode for Simultaneously Supporting Encryption, Message Authentication and Error Correction

We present MAGIC, a mode for authenticated encryption that simultaneously supports encryption, message authentication and error correction, all with the same code. In MAGIC, the same code employed for cryptographic integrity is also the parity used for error correction. To correct errors, MAGIC employs the Galois Hash transformation, which due to its bit linearity can perform corrections in a similar way as other codes do (e.g., Reed Solomon). To provide a cryptographically strong MAC, MAGIC encrypts the output of the Galois Hash using a secret key. To analyze the security of this construction we adapt the definition of the MAC adversary so that it is applicable to systems that combine message authentication with error correction. We demonstrate that MAGIC offers security in the order of O(2 to the N/2) with N being the tag size

DESIGN AND IMPLEMENTATION OF PATH FINDING AND VERIFICATION IN THE INTERNET

In the Internet, network traffic between endpoints typically follows one path that is determined by the control plane. Endpoints have little control over the choice of which path their network traffic takes and little ability to verify if the traffic indeed follows a specific path. With the emergence of software-defined networking (SDN), more control over connections can be exercised, and thus the opportunity for novel solutions exists. However, there remain concerns about the attack surface exposed by fine-grained control, which may allow attackers to inject and redirect traffic. To address these opportunities and concerns, we consider two specific challenges: (1) How can the network determine the choices of paths available to connect endpoints, especially when multiple criteria can be considered? And (2) how can endpoints verify the integrity of the path over which network traffic is sent. The latter consists of two subproblems, determining that the source of traffic is authentic and determining that a specified path is traversed without deviation. In this dissertation, we investigate and present solutions for both the network path finding problem and the verification problem. We first address path finding, or routing, which is a core functionality in the Internet. Existing approaches are either based on a single criterion (such as path length, delay, or an artificially defined ``weight’’) or use a combinatorial optimization function when there are multiple criteria. We present a multi-criteria routing algorithm that can search the whole space of all possible paths. To achieve the scalability of our solution, we limit the search to only Pareto-optimal paths, which allows us to prune sub-optimal paths quickly and reduce computational complexity. We show that our approach is tractable on a variety of realistic topologies and the results Pareto-optimal paths can be clustered to present a few alternative options. We then address path verification in the Internet, which consists of source authentication and path validation. Once a path has been selected, we show that an endpoint can validate that traffic indeed traverses along the chosen path. Prior work has relied on cryptographic approaches for such validation, which need significant computational resources. In contrast, we propose a lightweight and scalable technique to address this problem, which uses a set of orthogonal sequences as credentials in the packets. The verification of these orthogonal credentials is based on inner product computations, which can be easily implemented by basic bitwise operations in a processor. We show that the proposed approach can achieve the necessary security properties for both source authentication and path validation. Results from a prototype implementation show that the proposed technique can be implemented efficiently and only add a small computational overhead. The results of our work enable novel uses of networks with fine-grained traffic control, such as enabling more path choices in networks where multiple performance criteria matter. In addition, our work contributes to efforts to make the Internet more secure by presenting techniques that allow endpoints to validate the source and path of network traffic. We believe that these contributions help with improving both the current Internet and also future networks