Bo Sheng

Elliptic curve cryptography-based access control in sensor networks

Access control in sensor networks is used to authorise and grant users the right to access the network and data collected by sensors. Different users have different access right due to the access restriction implicated by the data security and confidentiality. Even though symmetric-key scheme, which has been investigated extensively for sensor networks, can fulfil the requirement, public-key cryptography is more flexible and simple rendering a clean interface for the security component. Against the popular belief that a public key scheme is not practical for sensor networks, this paper describes a public-key implementation of access control in a sensor network. We detail the implementation of Elliptic Curve Cryptography (ECC) over primary field, a public-key cryptography scheme, on TelosB, which is the latest sensor network platform. We evaluate the performance of our implementation and compare with other implementations we have ported to TelosB.

Counting RFID Tags Efficiently and Anonymously

Radio Frequency IDentification (RFID) technology has attracted much attention due to its variety of applications, e.g., inventory control and object tracking. One important problem in RFID systems is how to quickly estimate the number of distinct tags without reading each tag individually. This problem plays a crucial role in many real-time monitoring and privacy-preserving applications. In this paper, we present an efficient and anonymous scheme for tag population estimation. This scheme leverages the position of the first reply from a group of tags in a frame. Results from mathematical analysis and extensive simulation demonstrate that our scheme outperforms other protocols proposed in the previous work.

Secure and Serverless RFID Authentication and Search Protocols

With the increased popularity of RFID applications, different authentication schemes have been proposed to provide security and privacy protection for users. Most recent RFID protocols use a central database to store the RFID tag data. The RFID reader first queries the RFID tag and returns the reply to the database. After authentication, the database returns the tag data to the reader. In this paper, we propose a more flexible authentication protocol that provides comparable protection without the need for a central database. We also suggest a protocol for secure search for RFID tags. We believe that as RFID applications become widespread, the ability to securely search for RFID tags will be increasingly useful.

Outlier detection in sensor networks

Outlier detection has many important applications in sensor networks, e.g., abnormal event detection, animal behavior change, etc. It is a difficult problem since global information about data distributions must be known to identify outliers. In this paper, we use a histogram-based method for outlier detection to reduce communication cost. Rather than collecting all the data in one location for centralized processing, we propose collecting hints (in the form of a histogram) about the data distribution, and using the hints to filter out unnecessary data and identify potential outliers. We show that this method can be used for detecting outliers in terms of two different definitions. Our simulation results show that the histogram method can dramatically reduce the communication cost.

How to Monitor for Missing RFID tags

As RFID tags become more widespread, new approaches for managing larger numbers of RFID tags will be needed. In this paper, we consider the problem of how to accurately and efficiently monitor a set of RFID tags for missing tags. Our approach accurately monitors a set of tags without collecting IDs from them. It differs from traditional research which focuses on faster ways for collecting IDs from every tag. We present two monitoring protocols, one designed for a trusted reader and another for an untrusted reader.

Data storage placement in sensor networks

Data storage has become a important issue in sensor networks as a large amount of collected data need to be archived for future information retrieval. This paper introduces storage nodes to store the data collected from the sensors in their proximities. The storage nodes alleviate the heavy load of transmitting all the data to a central place for archiving and reduce the communicatio cost induced by the network query. This paper considers the storage node placement problem aiming to minimize the total energy cost for gathering data to the storage nodes and replying queries. We examine deterministic placement of storage odes and present optimal algorithms based on dy amic programming. Further, we give stochastic analysis for random deployment and conduct simulatio evaluatio for both deterministic and random placements of storage nodes.

Verifiable Privacy-Preserving Range Query in Two-Tiered Sensor Networks

We consider a sensor network that is not fully trusted and ask the question how we preserve privacy for the collected data and how we verify the data reply from the network. We explore the problem in the context of a network augmented with storage nodes and target at range query. We use bucketing scheme to mix the data for a range, use message encryption for data integrity, and employ encoding numbers to prevent the storage nodes from dropping data.

Severless Search and Authentication Protocols for RFID

With the increasing popularity of RFID applications, different authentication schemes have been proposed to provide security and privacy protection to users. Most recent RFID protocols use a central database to store the RFID tag data. An RFID reader first queries the RFID tag and returns the reply to the database. After authentication, the database returns the tag data to the reader. In this paper, we proposed a more flexible authentication protocol that provides comparable protection without the need for a central database. We also suggest a protocol for secure search for RFID tags. We believe that as RFID applications become widespread, the ability to search for RFID tags will be increasingly useful

Finding popular categories for RFID tags

As RFID tags are increasingly attached to everyday items, it quickly becomes impractical to collect data from every tag in order to extract useful information. In this paper, we consider the problem of identifying popular categories of RFID tags out of a large collection of tags, without reading all the tag data. We propose two algorithms based on the idea of group testing, which allows us to efficiently derive popular categories of tags. We evaluate our solutions using both theoretical analysis and simulation.

Efficient Tag Identification in Mobile RFID Systems

In this paper we consider how to efficiently identify tags on the moving conveyor. Considering conditions like the path loss and multi-path effect in realistic settings, we first propose a probabilistic model for RFID tag identification. Based on this model, we propose efficient solutions to identify moving RFID tags, according to the fixed-path mobility on the conveyor. A dynamic program based solution and an adaptive solution are proposed to select optimized frame sizes during the query cycles. Simulation results indicate that by leveraging the probabilistic model our solutions can achieve much better performance than using parameters for the ideal propagation situations.