A proxy-based mobile group membership protocol for large scale and highly dynamic groups

2005-2006 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

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\u27 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

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\u27 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

Group-Based Key Management Protocol for Energy Efficiency in Long-Lived and Large-Scale Distributed Sensor Networks

As wireless sensor networks grow, so does the need for effective security mechanisms. We propose a cryptographic key-management protocol, called energy-efficient key-management (EEKM) protocol. Using a location-based group key scheme, the protocol supports the revocation of compromised nodes and energy-efficient rekeying. The design is motivated by the observation that unicast-based rekeying does not meet the security requirements of periodic rekeying in long-lived wireless sensor networks. EEKM supports broadcast-based rekeying for low-energy key management and high resilience. In addition, to match the increasing complexity of encryption keys, the protocol uses a dynamic composition key scheme. EEKM also provides group-management protocols for secure group communication. We analyzed the energy efficiency and security of EEKM and compared it to other key-management protocols using a network simulator

Distributed Core Multicast (DCM): a multicast routing protocol for many groups with few receivers

We present a multicast routing protocol called Distributed Core Multicast (DCM). It is intended for use within a large single Internet domain network with a very large number of multicast groups with a small number of receivers. Such a case occurs, for example, when multicast addresses are allocated to mobile hosts, as a mechanism to manage Internet host mobility or in large distributed simulations. For such cases, existing dense or sparse mode multicast routing algorithms do not scale well with the number of multicast groups. DCM is based on an extension of the centre-based tree approach. It uses several core routers, called Distributed Core Routers (DCRs) and a special control protocol among them. DCM aims: (1) avoiding multicast group state information in backbone routers, (2) avoiding triangular routing across expensive backbone links, (3) scaling well with the number of multicast groups. We evaluate the performance of DCM and compare it to an existing sparse mode routing protocol when there is a large number of small multicast groups. We also analyse the behaviour of DCM when the number of receivers per group is not a small number

Study protocol; thyroid hormone replacement for untreated older adults with subclinical hypothyroidism - a randomised placebo controlled trial (TRUST)

Background: Subclinical hypothyroidism (SCH) is a common condition in elderly people, defined as elevated serum thyroid-stimulating hormone (TSH) with normal circulating free thyroxine (fT4). Evidence is lacking about the effect of thyroid hormone treatment. We describe the protocol of a large randomised controlled trial (RCT) of Levothyroxine treatment for SCH. Methods: Participants are community-dwelling subjects aged ≥65 years with SCH, diagnosed by elevated TSH levels (≥4.6 and ≤19.9 mU/L) on a minimum of two measures ≥ three months apart, with fT4 levels within laboratory reference range. The study is a randomised double-blind placebo-controlled parallel group trial, starting with levothyroxine 50 micrograms daily (25 micrograms in subjects <50Kg body weight or known coronary heart disease) with titration of dose in the active treatment group according to TSH level, and a mock titration in the placebo group. The primary outcomes are changes in two domains (hypothyroid symptoms and fatigue / vitality) on the thyroid-related quality of life questionnaire (ThyPRO) at one year. The study has 80% power (at p = 0.025, 2-tailed) to detect a change with levothyroxine treatment of 3.0% on the hypothyroid scale and 4.1% on the fatigue / vitality scale with a total target sample size of 750 patients. Secondary outcomes include general health-related quality of life (EuroQol), fatal and non-fatal cardiovascular events, handgrip strength, executive cognitive function (Letter Digit Coding Test), basic and instrumental activities of daily living, haemoglobin, blood pressure, weight, body mass index and waist circumference. Patients are monitored for specific adverse events of interest including incident atrial fibrillation, heart failure and bone fracture. Discussion: This large multicentre RCT of levothyroxine treatment of subclinical hypothyroidism is powered to detect clinically relevant change in symptoms / quality of life and is likely to be highly influential in guiding treatment of this common condition. Trial registration: Clinicaltrials.gov NCT01660126; registered 8th June 2012

Toward a framework for implementation of climate change treaty through self-enforcing mechanisms

Global warming caused by accumulation of emissions of greenhouse gases (GHGs) is a public bad, addressing which requires collective action by all the countries of the world. Under the United Nations Convention on Climate Change (UNFCCC), most countries have negotiated the Kyoto Protocol for GHG emissions control to stabilize climate change. Several issues about the Protocol remain unresolved -- first, most of the significant countries are required to take a decision on whether or not to sign such a protocol, which has large-scale implications for their energy and industrial sectors and economic well-being; second, climate change mitigation is a public good entailing that all the countries would stand to gain due to mitigation action taken by a sub-group of one or more countries; and third, there exists no supra-national authority to enforce such a protocol for the individual sovereign nations. Thus, commitment to cooperate on an international agreement on climate change control remains tenuous. Formally, such a cooperative model is likely to be unstable. The paper discusses the pros and cons of the already proposed international cooperative mechanisms toward climate change mitigation and highlights the problem of information revelation, particularly related to the abatement issues. In this context, it attempts to outline a structure of a self-enforcing burden sharing mechanism for climate change mitigation in an incomplete information framework. The mechanism is an adoption of the well-known Vickrey-Clarke-Groves mechanism, widely used in mechanism design theory.Climate change negotiations; cooperative games; stable coalitions; self-enforcing mechanism