A registry is a list of information recorded by a trusted authority. Registries have security requirements for data integrity and availability, and for the ability to connect with other registries. Building registries on a blockchain leverages key properties of blockchains, including data integrity, immutability, and availability. By using a blockchain as uniform infrastructure, different regis...

Blockchain protocols such as Bitcoin are gaining traction for exchanging payments in a secure and decentralized manner. Their need to achieve consensus across a large number of participants, however, fundamentally limits their performance. We describe Teechain, a new off-chain payment protocol that utilizes trusted execution environments (TEEs) to perform secure, efficient and scalable fund tra...

Conventional public key infrastructure (PKI) designs are not optimal and contain security flaws; there is much work underway in improving PKI. The properties given by the Bitcoin blockchain and its derivatives are a natural solution to some of the problems with PKI in particular, certificate transparency and elimination of single points of failure. Recently-proposed blockchain PKI designs are b...

The advent of Bitcoin paved the way for a plethora of blockchain systems supporting diverse applications beyond cryptocurrencies. Although in-depth studies of the protocols, security, and privacy of blockchains are available, there is no formal model of the transaction semantics that a blockchain is supposed to guarantee. In this work, we fill this gap, motivated by the observation that the sem...

Because of its potentially disruptive influence on business models (BMs), blockchain technology has sparked a lively debate among researchers. Our Delphi study sets out to explore the impact of blockchain in payments, which represents a major cornerstone of banking and the cradle of this technology. The results, grouped around four areas of thoughts, indicate that blockchain allows the offering...

Blockchain is a technology uniquely suited to support massive number of transactions and smart contracts within the Internet of Things (IoT) ecosystem, thanks to the decentralized accounting mechanism. In a blockchain network, the states of the accounts are stored and updated by the validator nodes, interconnected in a peer-to-peer fashion. IoT devices are characterized by relatively low comput...

Selfish mining is a well-known mining attack strategy discovered by Eyal and Sirer in 2014. After that, the attackers’ strategy space has been extended by many works. These works only analyze the strategy and behavior of one single attacker. The extension of the strategy space is based on the assumption that there is only one attacker in the blockchain network. However, a proof of work blockcha...

Blockchain technology enables the creation of a decentralized environment where transactions and data are not under the control of any third party organization. Any transaction ever completed is recorded in a public ledger in a verifiable and permanent way. Based on blockchain technology, we propose a global higher education credit platform, named EduCTX. This platform is based on the concept o...

Blockchain is offering new opportunities to develop new types of digital services. While research on the topic is still emerging, it has mostly focused on the technical and legal issues instead of taking advantage of this novel concept and creating advanced digital services. In this paper, we are going to leverage the open source Blockchain technology to propose a design for a new electronic vo...