We put forward a new framework that makes it possible to re-write or compress the content of any number of blocks in decentralized services exploiting the blockchain technology. As we argue, there are several reasons to prefer an editable blockchain, spanning from the necessity to remove inappropriate content and the possibility to support applications requiring re-writable storage, to “the rig...

Background: In recent years, blockchain technology has attracted considerable attention. It records cryptographic transactions in a public ledger that is difficult to alter and compromise because of the distributed consensus. As a result, blockchain is believed to resist fraud and hacking. Results: This work explores the types of fraud and malicious activities that can be prevented by blockchai...

We pose a fundamental problem of public blockchain, “incentive mismatch.” It is an open problem, but application portability is a provisional solution to the problem. Portability is also a desirable property for an application on a private blockchain. It is not even clear to be able to define a common API for various blockchain middlewares, but it is possible to improve portability by reducing ...

Plasma is a proposed framework for incentivized and enforced execution of smart contracts which is scalable to a significant amount of state updates per second (potentially billions) enabling the blockchain to be able to represent a significant amount of decentralized financial applications worldwide. These smart contracts are incentivized to continue operation autonomously via network transact...

At the beginning of 2018, there is a growing belief that blockchain technologies constitute a revolutionary innovation in how we transfer value electronically. In that vein, blockchain may be a suitable complement to ontologies to achieve a big part of Tim Berners-Lee’s vision of the semantic Web. We believe that if this complementarity is to be achieved blockchain and ontologies must co-evolve...

A blockchain is a public ledger for recording transactions, maintained by many nodes without central authority through a distributed cryptographic protocol. All nodes validate the information to be appended to the blockchain, and a consensus protocol ensures that the nodes agree on a unique order in which entries are appended. Distributed protocols tolerating faults and adversarial attacks, cou...

In this paper we address the issue of identity and access control within shared permissioned blockchains. We propose the ChainAchor system that provides anonymous but verifiable identities for entities on the blockchain. ChainAchor also provides access control to entities seeking to submit transactions to the blockchain to read/verify transactions on the the permissioned blockchain. Consensus n...

Recently, the Bitcoin-underlying blockchain technology gained prominence as a solution that offers the realization of distributed trust-free systems, where economic transactions are guaranteed by the underlying blockchain. We are still at an early stage and thus require a deeper understanding of how the blockchain potentials can be realized, and what are the opportunities and challenges in so d...

Research proposing the application of blockchain technology in accounting assumes the utilization of decentralized consensus mechanisms based on the exertion of scarce resources (Proof-of-Work; PoW), leading to the validation of transactions without the need of any third party. Together with the blockchain, a shared database, PoW is expected to lead to nearly immutable and, therefore, fraud-res...

Blockchain, introduced as the backbone of the Bitcoin cryptocurrency, is an emerging technology. Abstracting the currency logic away opens Blockchain to endless applications from finance to healthcare and Internet of Things. Asymmetric cryptography and more specifically digital signatures are a key component of the blockchain system. In this work, we introduce threshold signatures for the Hyper...