Large-scale RFID Systems Research Articles

Efficient Missing Key Tag Identification in Large-scale RFID Systems: An Iterative Verification and Selection Method

Efficient Missing Key Tag Identification in Large-scale RFID Systems: An Iterative Verification and Selection Method

An Efficient Early-breaking-estimation and Tree-splitting Missing RFID Tag Identification Protocol

Retailers grapple with inventory losses primarily due to missing items, prompting the need for efficient missing tag identification methods in large-scale RFID systems. Among them, few works considered the effect of unexpected unknown tags on the missing tag identification process. With the presence of unknown tags, some missing tags may be falsely identified as present. Thus, the system’s reliability is hardly guaranteed. To resolve these challenges, we propose an efficient early-breaking-estimation and tree-splitting-based missing tag identification (ETMTI) protocol for large-scale RFID systems. ETMTI employs innovative early-breaking-estimation and deactivation methods to swiftly handle unknown tags. Subsequently, a tree-splitting-based missing tag identification method is proposed, employing a B-ary splitting tree, to rapidly identify missing tags. Additionally, a bit-tracking response strategy is implemented to reduce processing time. Theoretical analysis is conducted to determine optimal parameters for ETMTI. Simulation results illustrate that our proposed ETMTI protocol significantly outperforms benchmark methods, offering a shorter processing time and a lower false negative rate.

Receive Only Necessary: Efficient Tag Category Identification in Large-Scale RFID Systems

RFID systems have been widely deployed for various applications such as inventory control, retail management, and object tracking. In many scenarios, coarse-grained system management of tag categories is more common than traditional system management of individual tags. Existing works on tag category management require knowing category IDs in advance, however, few protocols have been specially designed to obtain category IDs in multi-category RFID systems. In this paper, we propose <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CIP</i> , a time-efficient protocol specially designed to collect category IDs in multi-category RFID systems. The challenge in solving this problem is to avoid repeatedly collecting category IDs from multiple tags belonging to the same category. We address this challenge by squeezing tags in the same category into the same time slot and letting them reply to the reader simultaneously. Considering that the reader may receive signals from different tags in a slot, we exploit the Manchester coding to decode the aggregated signals. With this design, CIP collects each category ID only once and thus achieves high time efficiency by avoiding redundant identification of the same category ID. We further enhance CIP by utilizing the lightweight vectors to specify the order of tags’ replying and avoid useless slots. Rigorous theoretical analysis is presented to optimize the performance of CIP and guidelines on how to set optimal parameters to minimize the overall execution time are given. We conduct extensive experiments to evaluate the performance of our protocols. The experimental results show that our protocols can significantly improve time efficiency by 67 percent when compared with the state-of-the-art solutions.

BFSearch: Bloom filter based tag searching for large-scale RFID systems

Nowadays, RFID technology has been widely applied in inventory management, logistics tracking, identity recognition and so on. In an RFID-assisted large warehouse, customers often require the warehouse to provide the tag searching service to determine which given tags are present in the system. There are two major challenges in tag searching, one is how to exclude the interference caused by unexpected local tags, and the other is how to utilize the known IDs of wanted tags to improve the searching efficiency. In this paper, we propose a Bloom filter based tag searching protocol called BFSearch, which consists of two phases: non-wanted tag deactivation phase and target tag verification phase. In the non-wanted tag deactivation phase, we design a composite filter vector, which can deactivate the local tags that do not belong to the target tag set for eliminating their interference. We further propose an enhanced Bloom filter based tag searching protocol called BFSearch+, which implements a one-to-one correspondence between wanted tags and slots to discover the target tags. It can further improve the time efficiency by up to approximately 50%. Extensive theoretical analysis and simulations illustrate that the proposed BFSearch+ protocol outperforms the state-of-the-art ones.

A Cross Layer Protocol for Fast Identification of Blocked Tags in Large-scale RFID Systems

Blocker tag attack is one of the denial-of-service (DoS) attacks that threatens the privacy and security of RFID systems. The attacker interferes with the blocked tag by simulating a fake tag with the same ID, thus causing a collision of message replies. In many practical scenarios, the number of blocked tags may vary, or even be small. For example, the attacker may only block the important customers or high-value items. To avoid the disclosure of privacy and economic losses, it is of great importance to fast pinpoint these blocked ones. However, existing works do not take into account the impact of the number of blocked tags on the execution time and suffer from incomplete identification of blocked tags, long identification time or privacy leakage. To overcome these limits, we propose a cross layer blocked tag identification protocol (CLBI). CLBI consists of multiple rounds, in which it enables multiple unblocked tags to select one time slot and concurrently verify them by using tag estimation in physical layer. Benefiting from the utilization of most collision slots, the execution time can be greatly reduced. Furthermore, for efficient identification of blocked tags under different proportions, we propose a hybrid protocol named adaptive cross layer blocked tag identification protocol (A-CLBI), which estimates the remaining blocked tag in each round and adjusts the identification strategy accordingly. Extensive simulations show that our protocol outperforms state-of-the-art blocked tags identification protocol.

Efficient and Lightweight Batch Authentication for Large-Scale RFID Systems

In this letter, we propose an efficient and lightweight bloom-filter-based batch authentication (BBA) protocol. Comparing with existing complex data structures-based methods, BBA only requires the tags to construct a simple bloom filter vector distributively using the off-the-shelf on-tag hash functions, and can get the expected counterfeits estimation in just one round. We also provide rigorous theoretical certification to get the optimal parameter settings, so that the accuracy requirement can be guaranteed. To evaluate the performance of BBA, we conduct extensive simulations. The evaluation shows encouraging results in terms of estimation accuracy, as well as time efficiency.

Towards time-efficient localized polling for large-scale RFID systems

In this paper, we study the localized polling problem in large-scale RFID systems, i.e., how to efficiently collect information from wanted tags dM of total interrogated tags dN, where both dM and dN are unknown, but all the tags N including all the wanted tags M in the system have been collected in advance. This issue has great significance in many practical applications but appears to be challenging. Aiming at time efficiency, we propose a novel polling protocol called LocP, which consists of two phases: the Tags-Filtering phase and the Ordering-and-Reporting phase. LocP employs Bloom Filter twice to significantly reduce the scale of candidate tags in the Tags-Filtering phase. In the Ordering-and-Reporting phase, tags determine their own transmission time-slots according to the allocation vectors iteratively broadcasted by the reader. We conduct extensive simulations to evaluate the performance of LocP. The results demonstrate that LocP is highly efficient in terms of information collection time, leading to convincing applicability and scalability for large-scale RFID systems.

An Efficient Bit-Detecting Protocol for Continuous Tag Recognition in Mobile RFID Systems

In a mobile RFID system, a large number of tags move in and out of the system continuously, so that the reader has very limited time to recognize all the tags. As a result, the effective and efficient identification of tags in mobile environments is a more challenging problem compared to conventional static RFID systems. In this paper, we propose an efficient bit-detecting (EBD) protocol to accelerate the reading process of large-scale mobile RFID systems. In these systems, some previously recognized tags, i.e., known tags, may stay in the reader's reading range for two consecutive reading cycles, and some unknown tags may newly participate in the current reading cycle. In the proposed EBD protocol, a new bit monitoring method is proposed to detect the presence of known tags using a small number of slots, and to retrieve their IDs from the back-end database. Next, an $M$ -ary bit-detecting tree recognition method is proposed to rapidly recognize unknown tags without generating any idle slots. This new protocol is shown to perform better than existing methods reported in the literature. Both theoretic and simulation results are present to demonstrate that the proposed protocol is superior to existing protocols in terms of lower time cost.

Minimal Perfect Hashing-Based Information Collection Protocol for RFID Systems

For large-scale RFID systems, this paper studies the practically important problem of target tag information collection, which aims at collecting information from a specific set of target tags instead of all. However, the existing solutions are of low time-efficiency because of two reasons. First, the serious collisions among tags due to hashing randomness seriously reduce the frame utilization, whose upper bound is just 36.8 percent. Second, they cannot efficiently distinguish the target tags from the non-target tags and thus inevitably collect a lot of irrelevant information on non-target tags, which further deteriorates the effective utilization of the time frame. To overcome the above two drawbacks, this paper proposes the minimal Perfect hashing-based Information Collection (PIC) protocol, which first leverages lightweight indicator vectors to establish a one-to-one mapping between target tags and slots, thereby improving the frame utilization to nearly 100 percent; and then uses the novel data structure called Minimal Perfect Hashing based Filter (MPHF) to filter out the non-target tags, thereby preventing them from interfering with the process of collecting information from target tags. Sufficient theoretical analyses are also presented in this paper to minimize the execution time of the proposed PIC protocol. Extensive simulations are conducted to compare the proposed PIC protocol with prior works side-by-side. The simulation results demonstrate that PIC significantly outperforms the state-of-the-art protocols in terms of time-efficiency.

An Effective Way to Search Tags from Large Scale RFID System

An Effective Way to Search Tags from Large Scale RFID System

BFCE: A Constant-time cardinality estimator for large-scale RFID systems

Cardinality estimation is of primary importance in many RFID systems and applications. To ensure the time efficiency of estimation, numerous probability-based approaches have been proposed, most of which aim at meeting arbitrary accuracy requirement and follow a similar way of only minimizing the number of required time slots from tags to reader. In this paper, we propose BFCE, a constant-time Bloom Filter based Cardinality Estimator, for particular scenarios where slightly low accuracy and high efficiency are pursued. Comparing with existing approaches, BFCE only needs constant number of bit-slots, and the overall communication overhead is also significantly cut down, as the reader only needs to broadcast a constant number of messages for parameter setting. Results from extensive simulations under various tagIDs distributions shows that BFCE is accurate and highly efficient. In terms of the overall execution time, BFCE is 30 times faster than ZOE and 2 times faster than SRC in average, the two state-of-the-arts estimation approaches.

Fast temporal continuous scanning in RFID systems

This paper studies the problem of temporal continuous scanning for large-scale RFID systems, which is an essential operation to keep the inventory up-to-date. The existing solutions need to execute unknown and missing tag identification protocols separately, which are of low time-efficiency because the unknown tags disturb the identification of missing tags and vice versa. To this end, we design a Fast Continuous Scanning (FCS) protocol based on the proposed multiple categories filter which can detect unknown tags and skip the empty and collision slots for improving the efficiency of missing tag identification. FCS is faster than the prior methods because the proposed filter is helpful to decreasing the interference between unknown and missing tags. We also investigate the optimization of the involved parameters to minimize the execution time. Extensive simulation results demonstrate that the proposed protocol outperforms the state-of-the-art solutions by saving 39% ∼ 58.5% of the execution time.

AnonPri: A secure anonymous private authentication protocol for RFID systems

Privacy preservation in RFID systems is a very important issue in modern day world. Privacy activists have been worried about the invasion of user privacy while using various RFID systems and services. Hence, significant efforts have been made to design RFID systems that preserve users' privacy. Majority of the privacy preserving protocols for RFID systems require the reader to search all tags in the system in order to identify a single RFID tag which not efficient for large scale systems. In order to achieve high-speed authentication in large-scale RFID systems, researchers propose tree-based approaches, in which any pair of tags share a number of key components. Another technique is to perform group-based authentication that improves the tradeoff between scalability and privacy by dividing the tags into a number of groups. This novel authentication scheme ensures privacy of the tags. However, the level of privacy provided by the scheme decreases as more and more tags are compromised. To address this issue, in this paper, we propose a group based anonymous private authentication protocol (AnonPri) that provides higher level of privacy than the above mentioned group based scheme and achieves better efficiency (in terms of providing privacy) than the approaches that prompt the reader to perform an exhaustive search. Our protocol guarantees that the adversary cannot link the tag responses even if she can learn the identifier of the tags. Our evaluation results demonstrates that the level of privacy provided by AnonPri is higher than that of the group based authentication technique.

Efficient tag reading protocol for large-scale RFID systems with pre-reading

In large-scale RFID systems, collecting all of the tag IDs is a time-consuming process. A protocol designated as Smart Trend-Traversal (STT) has been proposed to reduce collisions during the tag collection process and to dynamically construct the query strings used to interrogate the tags. In general, if the tag ID information is known to the reader from a previous tag collection round, the efficiency of the current round can be significantly improved. Various protocols have been proposed for scanning a known tag set based on the use of a hash function. Accordingly, the present study proposes an Enhanced STT scheme based on a blocking protocol and a Distributed Record Tag-Check (DRTC) mechanism. Compared to the conventional STT scheme, the proposed protocol adaptively adjusts the length of the query string depending on the response received to the previous query. Moreover, in the DRTC mechanism, the tags determine their transmission slot frame directly without the assistance of the reader, and thus the overall overhead of the tag-collection process is reduced. The simulation results show that the Enhanced STT scheme reduces the total number of queries required to collect the entire tag set compared to the conventional STT method. Moreover, the proposed DRTC mechanism yields an effective reduction in the total number of frame slots compared to existing protocols such as TPP/CSTR and ECRB.

Private and Secure Tag Access for Large-Scale RFID Systems

The performance of key authentication and the degree of privacy in large-scale RFID systems are considered by many researchers as tradeoffs. Based on how keys are managed in the system, the privacy preserving tag authentications proposed in the past can be categorized into tree-based and group-based approaches. While a tree-based approach achieves high performance in key authentication, it suffers from the issue of low privacy should a fraction of tags be compromised. On the contrary, while group-based key authentication is relatively invulnerable to compromise attacks, it is not scalable to a large number of tags. In this paper, we propose a new private tag authentication protocol based on skip lists, named randomized skip lists-based authentication (RSLA). Without sacrificing the authentication performance, RSLA provides a high privacy preserving mechanism. While RSLA provides the same level of unpredictability-based-privacy and indistinguishability-based privacy compared with other structured key management approaches, our scheme achieves the highest system anonymity with good performance in key look up and update. In addition, the simulation results match our analyses closely.

Channel-Oblivious Counting Algorithms for Large-Scale RFID Systems

Scalable, low-latency and accurate RFID counting algorithms have recently been proposed as a fundamental building block to support more complex query operations in a large-scale RFID system. One distinct feature of these algorithms is that they do not require explicit identification of individual tags and therefore can eliminate the latency bottleneck caused by serialization during multiple access control. However, these algorithms all assume reliable communications between the reader and the tags. While this assumption is also adopted by many tag-identification protocols in the current RFID standards, it is practically unachievable given the current technology and low-cost requirement of RFID tags. In fact, recent empirical studies have found that the communication between an RFID reader and a set of seemingly “in-range” tags are still unreliable and highly non-deterministic due to the varying channel conditions. In this paper, we discuss the design and performance analysis of a set of channel-oblivious RFID counting algorithms which can estimate the size of a tag-set of interest over unreliable wireless channels. The proposed schemes can provide accurate cardinality estimates without any prior knowledge of the channel parameters. We first propose a series of algorithms and analyze their performance under a simplified memoryless lossy channel model. We then extend them to handle the impact due to backscattering effects and correlated losses found in practical RFID systems. Our proposed designs only require simple modifications to standard RFID tags and readers and can be implemented using current technologies with minimal increase in tag/ reader cost. Our designs can also be extended to other RFID counting algorithms which assumed reliable communication channels.

SA-PSO based optimizing reader deployment in large-scale RFID Systems

The RFID technologies are expected to revolutionize various industrial areas and the application of large-scale RFID systems has been a trend. Satisfying a set of imperative constrains and optimizing a set of objectives, the reader deployment is the primary problem for the most challenging RFID network planning (RNP), and needs to be reasonably solved to operate the large-scale RFID systems in an optimal fashion. By taking the coverage, signal interference and load balance as the optimization objectives and deducing the objective ranges, the reader deployment is conducted as a problem of multi-objectives combination optimization. And then, by introducing the Metropolis rule of Simulated Annealing Algorithm, an improved Particle Swarm Algorithm is proposed (SA-PSO) to solve this problem, which can restrict the position change of original and new particles in the iteration process and accelerate the convergence speed of the algorithm. The simulation results show that the addressed SA-PSO algorithm is superior to the compared algorithms in coverage optimization, and the whole system performance can be enhanced by optimizing the signal interference and load balance among the deployed readers.

Editorial: special issue on advances in security and privacy for future mobile communications

Recent advances in wireless communication technologies along with a proliferation of mobile devices have enabled a new, and expanded level of ubiquitous access to data and communications. Reliable, secure, and private communications are as essential in these product offerings as network availability, especially as the Internet presents enhanced opportunities for network breaches. Every day new security challenges surface, often a consequence of weak encryption and inherently open access to networks and in some cases lack of a pre-deployed infrastructure. This special issue advances the state-of-the-art research in the area of security, privacy, cryptography, and its applications to future mobile communications. Our special issue emphasizes potential contributions to security and privacy preserving applications and services in the mobile ecosystem. It contains seven papers, in print and online release, covering anonymous RA for trusted computing, cooperative security system for m-Health applications, security solutions for the IMS media plane, a comprehensive survey on Anonymous Voice over IP (VoIP) communication, and an untraceable authentication method for large-scale active-tag RFID systems. These papers will hopefully stimulate further research in this important topic.

ECC-based untraceable authentication for large-scale active-tag RFID systems

Radio frequency identification tag authentication protocols are generally classified as non-full-fledged and full-fledged, according to the resource usage of the tags. The non-full-fledged protocol...

Efficient detection of counterfeit products in large-scale RFID systems using batch authentication protocols

RFID technology facilitates processing of product information, making it a promising technology for anti-counterfeiting. However, in large-scale RFID applications, such as supply chain, retail industry, pharmaceutical industry, total tag estimation and tag authentication are two major research issues. Though there are per-tag authentication protocols and probabilistic approaches for total tag estimation in RFID systems, the RFID authentication protocols are mainly per-tag-based where the reader authenticates one tag at each time. For a batch of tags, current RFID systems have to identify them and then authenticate each tag sequentially, one at a time. This increases the protocol execution time due to the large volume of authentication data. In this paper, we propose to detect counterfeit tags in large-scale system using efficient batch authentication protocol. We propose FSA-based protocol, FTest, to meet the requirements of prompt and reliable batch authentication in large-scale RFID applications. FTest can determine the validity of a batch of tags with minimal execution time which is a major goal of large-scale RFID systems. FTest can reduce protocol execution time by ensuring that the percentage of potential counterfeit products is under the user-defined threshold. The experimental result demonstrates that FTest performs significantly better than the existing counterfeit detection approaches, for example, existing authentication techniques.