Demystifying incentives in the consensus computer

Cryptocurrencies like Bitcoin and the more recent Ethereum system allow users to specify scripts in transactions and contracts to support applications beyond simple cash transactions. In this work, we analyze the extent to which these systems can enforce the correct semantics of scripts. We show that when a script execution requires nontrivial computation effort, practical attacks exist which either waste miners\u27 computational resources or lead miners to accept incorrect script results. These attacks drive miners to an ill-fated choice, which we call the {\em verifier\u27s dilemma}, whereby rational miners are well-incentivized to accept unvalidated blockchains. We call the framework of computation through a scriptable cryptocurrency a consensus computer and develop a model that captures incentives for verifying computation in it. We propose a resolution to the verifier\u27s dilemma which incentivizes correct execution of certain applications, including outsourced computation, where scripts require minimal time to verify. Finally we discuss two distinct, practical implementations of our consensus computer in real cryptocurrency networks like Ethereum

Atomic Information Disclosure of Off-Chained Computations Using Threshold Encryption

Public Blockchains on their own are, by definition, incapable of keeping data private and disclosing it at a later time. Control over the eventual disclosure of private data must be maintained outside a Blockchain by withholding and later publishing encryption keys, for example. We propose the Atomic Information Disclosure (AID) pattern based on threshold encryption that allows a set of key holders to govern the release of data without having access to it. We motivate this pattern with problems that require independently reproduced solutions. By keeping submissions private until a deadline expires, participants are unable to plagiarise and must therefore generate their own solutions which can then be aggregated and analysed to determine a final answer. We outline the importance of a game-theoretically sound incentive scheme, possible attacks, and other future work

Blockchain and Smart Contracts: Disruptive Technologies for the Insurance Market

Blockchain technologies paired with smart contracts exhibit the potential to transform the global insurance industry. The recent evolution of smart contracts and their fast adoption allow to rethink processes and to challenge traditional structures. Therefore, a special focus is on the analysis of the underlying technology and recent improvements. Further, we provide an overview of how the insurance sector may be affected by blockchain technology. We emphasize current challenges and limitations through analyzing two promising use cases in this area. We find that realizing the full potential of the blockchain technology requires overcoming several challenges including scalability, the incorporation of external information, flexibility, and permissioning schemes