Basel Alomair

Scalable RFID systems: a privacy-preserving protocol with constant-time identification

In RFID literature, most “privacy-preserving” protocols require the reader to search all tags in the system in order to identify a single tag. In another class of protocols, the search complexity is reduced to be logarithmic in the number of tags, but it comes with two major drawbacks: it requires a large communication overhead over the fragile wireless channel, and the compromise of a tag in the system reveals secret information about other, uncompromised, tags in the same system. In this work, we take a different approach to address time complexity of private identification in large-scale RFID systems. We utilize the special architecture of RFID systems to propose a symmetric-key privacy-preserving authentication protocol for RFID systems with constant-time identification. Instead of increasing communication overhead, the existence of a large storage device in RFID systems, the database, is utilized for improving the time efficiency of tag identification.

Review: Privacy versus scalability in radio frequency identification systems

Embedding a Radio Frequency Identification (RFID) tag into individual items enables the unique identification of such items over the wireless medium, without the need for a line-of-sight path. One of the main challenges for the successful commercialization of the RFID technology is the efficient, yet private, identification of low-cost tags in the presence of adversaries attempting to illegally track users via tags in their possession. An RFID system consists of two functional components, namely, the interactive protocol between RFID reader-tag pairs and the reader-database information retrieval mechanism. Because of the large number of tags in a typical RFID system, the private identification of tags can be a challenging problem. In this paper, we investigate privacy-preserving RFID systems and classify them based on the computational efficiency of tag identification. We show the close relation between the degree of privacy achieved by the reader-tag interaction and the reader-database information retrieval complexity.

Passive attacks on a class of authentication protocols for RFID

Mutual authentication mechanisms can be used in RFID systems to preserve the confidentiality of the RFID tags. Hiding the unique IDs of the tags is critical to prevent unauthorized tag tracking. In this paper, we analyze two mutual authentication protocols called M2AP and EMAP, recently proposed by Peris-Lopez et. al. We show that a passive adversary eavesdropping on the open wireless medium, can extract the unique ID of the RFID tag by collecting an expected O(log2 L) challenge-response exchange messages between the tag and the reader, where L is the length of the tags unique ID. To date, previously known attacks on M2AP and EMAP require the active probing of each tag. Furthermore, attacks on M2AP require O(L) active queries to be sent to the tag by a rogue reader, as opposed to O(log2 L).

Securing low-cost RFID systems: An unconditionally secure approach

In this paper, we explore a new direction towards solving the identity authentication problem in RFID systems. We break the RFID authentication process into two main problems: message authentication and random number generation. For parties equipped with a good source of randomness and a secure cryptographic primitive to authenticate messages, the literature of cryptography is rich with well-studied solutions for secure identity authentication. However, the two operations, random number generation and message authentication, can be expensive for low-cost RFID tags. In this paper, we lay down the foundations of a new direction towards solving these problems in RFID systems. We propose an unconditionally secure direction for authenticating RFID systems. We use the fact that RFID readers are computationally powerful devices to design a protocol that allows RFID readers to deliver random numbers to RFID tags in an unconditionally secure manner. Then, by taking advantage of the information-theoretic security of the transmitted messages, we develop a novel unconditionally secure message authentication code that is computed with a single multiplication operation. The goal of this work is to bring more research to the design of such unconditionally secure protocols, as opposed to the computationally secure protocols that have been proposed extensively, for the purpose of suiting the stringent computational capabilities of low-cost devices.

Scalable RFID Systems: A Privacy-Preserving Protocol with Constant-Time Identification

In RFID literature, most “privacy-preserving” protocols require the reader to search all tags in the system in order to identify a single tag. In another class of protocols, the search complexity is reduced to be logarithmic in the number of tags, but it comes with two major drawbacks: it requires a large communication overhead over the fragile wireless channel, and the compromise of a tag in the system reveals secret information about other, uncompromised, tags in the same system. In this work, we take a different approach to address time complexity of private identification in large-scale RFID systems. We utilize the special architecture of RFID systems to propose a symmetric-key privacy-preserving authentication protocol for RFID systems with constant-time identification. Instead of increasing communication overhead, the existence of a large storage device in RFID systems, the database, is utilized for improving the time efficiency of tag identification.

Efficient Authentication for Mobile and Pervasive Computing

With todays technology, many applications rely on the existence of small devices that can exchange information and form communication networks. In a significant portion of such applications, the confidentiality and integrity of the communicated messages are of particular interest. In this work, we propose two novel techniques for authenticating short encrypted messages that are directed to meet the requirements of mobile and pervasive applications. By taking advantage of the fact that the message to be authenticated must also be encrypted, we propose provably secure authentication codes that are more efficient than any message authentication code in the literature. The key idea behind the proposed techniques is to utilize the security that the encryption algorithm can provide to design more efficient authentication mechanisms, as opposed to using standalone authentication primitives.

The power of primes: security of authentication based on a universal hash-function family

Abstract Message authentication codes (MACs) based on universal hash-function families are becoming increasingly popular due to their fast implementation. In this paper, we investigate a family of universal hash functions that has been appeared repeatedly in the literature and provide a detailed algebraic analysis for the security of authentication codes based on this universal hash family. In particular, the universal hash family under analysis, as appeared in the literature, uses operation in the finite field ℤ p . No previous work has studied the extension of such universal hash family when computations are performed modulo a non-prime integer n. In this work, we provide the first such analysis. We investigate the security of authentication when computations are performed over arbitrary finite integer rings ℤ n and derive an explicit relation between the prime factorization of n and the bound on the probability of successful forgery. More specifically, we show that the probability of successful forgery against authentication codes based on such a universal hash-function family is bounded by the reciprocal of the smallest prime factor of the modulus n.

Efficient Generic Forward-Secure Signatures and Proxy Signatures

We propose a generic method to construct forward-secure signature schemes from standard signature schemes. The proposed construction is more computationally efficient than previously proposed schemes. In particular, the key updating operation in the proposed scheme is orders of magnitude more computationally efficient than previous schemes, making it attractive for a variety of applications, such as electronic checkbooks. Another advantage of our proposed scheme is the ability to be easily extended to proxy signature schemes. We define two notions of forward-security in the proxy signature setup, namely, strong forward-secure proxy signatures and weak forward-secure proxy signatures. We then describe a construction of a scheme that satisfies the strong forward-secure proxy signature property.

Submodularity in Dynamics and Control of Networked Systems

This book presents a framework for the control of networked systems utilizing submodular optimization techniques. The main focus is on selecting input nodes for the control of networked systems, an inherently discrete optimization problem with applications in power system stability, social influence dynamics, and the control of vehicle formations. The first part of the book is devoted to background information on submodular functions, matroids, and submodular optimization, and presents algorithms for distributed submodular optimization that are scalable to large networked systems.In turn, the second part develops a unifying submodular optimization approach to controlling networked systems based on multiple performance and controllability criteria. Techniques are introduced for selecting input nodes to ensure smooth convergence, synchronization, and robustness to environmental and adversarial noise. Submodular optimization is the first unifying approach towards guaranteeing both performance and controllability with provable optimality bounds in static as well as time-varying networks. Throughout the text, the submodular framework is illustrated with the help of numerical examples and application-based case studies in biological, energy and vehicular systems.The book effectively combines two areas of growing interest, and will be especially useful for researchers in control theory, applied mathematics, networking or machine learning with experience in submodular optimization but who are less familiar with the problems and tools available for networked systems (or vice versa). It will also benefit graduate students, offering consistent terminology and notation that greatly reduces the initial effort associated with beginning a course of study in a new area.

Leader selection in multi-agent systems for smooth convergence via fast mixing

In a leader-follower multi-agent system (MAS), a set of leader nodes receive state updates directly from the network operator. The follower nodes then compute their states based on the inputs from the leader nodes. In this paper, we study the problem of selecting a set of leader nodes in order to minimize the time required for the distributed coordination law used by the MAS to converge. We first represent the convergence time of a MAS in terms of the mixing time of a random walk on the underlying network graph. We then study two leader selection problems as convex optimization problems of fast mixing. First, we formulate the problem of selecting a fixed number of leaders in order to minimize the convergence time. We then study the problem of finding the minimumsize set of leaders in order to satisfy a constraint on the convergence time. We develop leader selection algorithms based on supergradient descent methods for static network topologies as well as a MAS experiencing random link failures and a MAS that switches between predefined topologies. We compare our leader selection algorithms with random and degree-based leader selection for both static and dynamic networks through simulation study. From the simulation comparisons, we note that the convergence rate of fast mixing is faster than that of degree-based methods. We also note that the fast mixing requires smallest number of leaders to achieve a given bound on the convergence time.