A Privacy Preserving Framework for RFID Based Healthcare Systems

RFID (Radio Frequency IDentification) is anticipated to be a core technology that will be used in many practical applications of our life in near future. It has received considerable attention within the healthcare for almost a decade now. The technology’s promise to efficiently track hospital supplies, medical equipment, medications and patients is an attractive proposition to the healthcare industry. However, the prospect of wide spread use of RFID tags in the healthcare area has also triggered discussions regarding privacy, particularly because RFID data in transit may easily be intercepted and can be send to track its user (owner). In a nutshell, this technology has not really seen its true potential in healthcare industry since privacy concerns raised by the tag bearers are not properly addressed by existing identification techniques. There are two major types of privacy preservation techniques that are required in an RFID based healthcare system—(1) a privacy preserving authentication protocol is required while sensing RFID tags for different identification and monitoring purposes, and (2) a privacy preserving access control mechanism is required to restrict unauthorized access of private information while providing healthcare services using the tag ID. In this paper, we propose a framework (PriSens-HSAC) that makes an effort to address the above mentioned two privacy issues. To the best of our knowledge, it is the first framework to provide increased privacy in RFID based healthcare systems, using RFID authentication along with access control technique

A Treasury System for Cryptocurrencies: Enabling Better Collaborative Intelligence

A treasury system is a community controlled and decentralized collaborative decision-making mechanism for sustainable funding of the blockchain development and maintenance. During each treasury period, project proposals are submitted, discussed, and voted for; top-ranked projects are funded from the treasury. The Dash governance system is a real-world example of such kind of systems. In this work, we, for the first time, provide a rigorous study of the treasury system. We modeled, designed, and implemented a provably secure treasury system that is compatible with most existing blockchain infrastructures, such as Bitcoin, Ethereum, etc. More specifically, the proposed treasury system supports liquid democracy/delegative voting for better collaborative intelligence. Namely, the stake holders can either vote directly on the proposed projects or delegate their votes to experts. Its core component is a distributed universally composable secure end-to-end verifiable voting protocol. The integrity of the treasury voting decisions is guaranteed even when all the voting committee members are corrupted. To further improve efficiency, we proposed the world’s first honest verifier zero-knowledge proof for unit vector encryption with logarithmic size communication. This partial result may be of independent interest to other cryptographic protocols. A pilot system is implemented in Scala over the Scorex 2.0 framework, and its benchmark results indicate that the proposed system can support tens of thousands of treasury participants with high efficiency

A Treasury System for Cryptocurrencies:Enabling Better Collaborative Intelligence

A treasury system is a community-controlled and decentralized collaborative decision-making mechanism for sustainable funding of blockchain development and maintenance. During each treasury period, project proposals are submitted, discussed, and voted for; top-ranked projects are funded from the treasury. The Dash governance system is a real-world example of such kind of systems. In this work, we, for the first time, provide a rigorous study of the treasury system. We modelled, designed, and implemented a provably secure treasury system that is compatible with most existing blockchain infrastructures, such as Bitcoin, Ethereum, etc. More specifically, the proposed treasury system supports liquid democracy/delegative voting for better collaborative intelligence. Namely, the stake holders can either vote directly on the proposed projects or delegate their votes to experts. Its core component is a distributed universally composable secure end-to-end verifiable voting protocol. The integrity of the treasury voting decisions is guaranteed even when all the voting committee members are corrupted. To further improve efficiency, we proposed the world’s first honest verifier zero-knowledge proof for unit vector encryption with logarithmic size communication. This partial result may be of independent interest to other cryptographic protocols. A pilot system is implemented in Scala over the Scorex 2.0 framework, and its benchmark results indicate that the proposed system can support tens of thousands of treasury participants with high efficiency

Towards Sustainable Blockchains:Cryptocurrency Treasury and General Decision-making Systems with Provably Secure Delegable Blockchain-based Voting

The blockchain technology and cryptocurrencies, its most prevalent application, continue to gain acceptance and wide traction in research and practice within academia and the industry because of its promise in decentralised and distributed computing. Notably, the meteoric rise in the value and number of cryptocurrencies since the creation of Bitcoin in 2009 have ushered in newer innovations and interventions that addressed some of the prominent issues that affect these platforms. Despite the increased privacy, security, scalability, and energy-saving capabilities of new consensus protocols in newer systems, the development and management of blockchains, mostly, do not reflect the decentralisation principle despite blockchains being decentralised and distributed in their architecture. The concept of treasury has been identified as a tool to address this problem. We explore the idea of blockchain treasury systems within literature and practice, especially with relation to funding and decision-making power towards blockchain development and maintenance. Consequently, we propose a taxonomy for treasury models within cryptocurrencies. Thereafter, we propose an efficient community-controlled and decentralised collaborative decision-making mechanism to support the development and management of blockchains. Our proposed system incentivises participants and is proven secure under the universally composable (UC) framework while also addressing gaps identified from our investigation of prior systems e.g. non-private ballots and insecure voting. Furthermore, we adapt our system and propose a privacy-preserving general decision making system for blockchain governance that supports privacy-centric cryptocurrencies. Besides, using a set of metrics, we introduce a consensus analysis mechanism to enhance the utility of decision-making of the systems by evaluating individual choices against collective (system-wide) decisions. Finally, we provide pilot system implementations with benchmark results confirming the efficiency and practicality of our constructions

Blockchain Securities Issues: Decentralized Identity System With Key Management Perspective

Blockchain was created many years ago to solve the problems of data transfer Integrity, several years later the issues persist. Blockchain securities are one of the most important considerations to be investigated, and data integrity is about ensuring the accuracy and validity of messages such that when they are read, they are the same as when they were first written. It is of the opinion that passing information across from one person to another cannot be the same as it was first said at the onset. Our work investigated Blockchain security issues, studying Integrity emanating from transactions across the blocks and how to deal with the securities issues. It also investigated decentralization and issues in blockchain to investigate how to mitigate the security issues associated with blockchain. It further discusses the use of key management in solving security issues in blockchain, viewing different key management systems of private and public keys, and solutions in addressing the blockchain problems. Lastly, we contributed the use of Decentralized Identity systems (DIDs) into the blockchain where we use a unique identifier, “ID.me” to verifier the individual credentials before any transaction, this was done by sending a digital ID through the issuer to the verifier to authenticate the integrity and identity of the holder and this proof worthy of protecting the information and maintaining the privacy of the user of the blockchain technology

Advances in signatures, encryption, and E-Cash from bilinear groups

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 147-161).We present new formal definitions, algorithms, and motivating applications for three natural cryptographic constructions. Our constructions are based on a special type of algebraic group called bilinear groups. 1. Re-Signatures: We present the first public key signature scheme where a semi-trusted proxy, given special information, can translate Alice's signature on a message into Bob's signature on the same message. The special information, however, allows nothing else, i.e., the proxy cannot translate from Bob to Alice, nor can it sign on behalf of either Alice or Bob. We show that a path through a graph can be cheaply authenticated using this scheme, with applications to electronic passports. 2. Re-Encryption: We present the first public key cryptosystem where a semi-trusted proxy, given special information, can translate an encryption of a message under Alice's key into an encryption of the same message under Bob's key. Again, the special information allows nothing else, i.e. the proxy cannot translate from Bob to Alice, decrypt on behalf of either Alice or Bob, or learn anything else about the message. We apply this scheme to create a new mechanism for secure distributed storage.(cont.) 3. Compact; E-Cash with Tracing and Bounded-Anonymity: We present an offline e-cash system where 2 coins can be stored in O(e + k) bits and withdrawn or spent in 0(f + k) time, where k is the security parameter. The best previously known schemes required at least one of these complexities to be 0(2t . k). In our system, a user's transactions are anonymous and unlinkable, unless she performs a forbidden action, such as double-spending a coin. Performing a forbidden action reveals the identity of the user, and optionally allows to trace all of her past transactions. We provide solutions without using a trusted party. We argue why features of our system are likely to be crucial to the adoption of any e-cash system.by Susan Hohenberger.Ph.D

An Analysis of Chaum's Voter-Verifiable Election Scheme

Chaum's Voter-Verifiable election scheme introduces a new direction for electronic voting. The scheme eliminates the need to trust any machinery or authority, and instead relies on mathematical proof to certify the trustworthiness of an election. Audits at every stage of the election create transparency that should restore voter confidence in the election process. We survey and categorize the field of electronic voting, and place Chaum's scheme within this context. We then define a framework of formal requirements of a voting system. We present Chaum's scheme itself, and give an analysis. Based on our technical analysis, we find the scheme to be secure. However, after considering other implementation concerns, we recognize various minor obstacles limiting its widespread adoption in today's elections. Despite this, we believe that the substance of the scheme is promising and maybe an improved, simpler variant might better suit future elections

Matters of Coercion-Resistance in Cryptographic Voting Schemes

This work addresses coercion-resistance in cryptographic voting schemes. It focuses on three particularly challenging cases: write-in candidates, internet elections and delegated voting. Furthermore, this work presents a taxonomy for analyzing and comparing a huge variety of voting schemes, and presents practical experiences with the voting scheme Bingo Voting