Mark S. Miller1, Tom Van Cutsem2, and Bill Tulloh

Abstract. Contracts enable mutually suspicious parties to cooperate safely through the exchange of rights. Smart contracts are programs whose behavior enforces the terms of the contract. This paper shows how such contracts can be specified elegantly and executed safely, given an appropriate distributed, secure, persistent, and ubiquitous computational fabric. JavaScript provides the ubiquity but must be significantly extended to deal with the other aspects. The first part of this paper is a progress report on our efforts to turn JavaScript into this fabric. To demonstrate the suitability of this design, we describe an escrow exchange contract implemented in 42 lines of JavaScript code.

Keywords: security, distributed objects, object-capabilities, smart contracts.

Smart Contracts for the Rest of Us

The fabric of the global economy is held together by contracts. A contract is an agreed framework for the rearrangement of rights between mutually suspicious parties. But existing contracts are ambiguous, jurisdictions-specific, and written, interpreted, and adjudicated only by expensive experts. Smart contracts are contract-like arrangements expressed in program code, where the behavior of the program enforces the terms of the “contract”[1]. Though not a substitute for legal contracts, they can provide some of the benefits of contracts for fine-grain, jurisdiction-free, and automated arrangements for which legal contracts are impractical. To realize this potential, smart contracts need a distributed, secure, persistent, and ubiquitous computational fabric. To avoid merely substituting one set of expensive experts for another, non-experts should be able to write smart contracts understandable by other non-experts. We1 are working towards turning JavaScript into such a fabric. JavaScript is already understood and used by many non-expert programmers. We call our target JavaScript platform Dr. SES for Distributed Resilient Secure EcmaScript. 2 Dr. SES is not specifically tied to electronic rights (erights) or smart contracts per se. Its focus is to make distributed secure programming in JavaScript as effortless as possible. But much of the design of Dr. SES and its predecessors [2,3,4] was shaped by examining what we need to express smart contracts simply. Taking a rights-based approach to local and distributed computing, we believe, has led us to building a better general purpose platform as well as one naturally suited for expressing new kinds of erights and contracts.