Towards Safer Smart Contracts: A Survey of Languages and Verification Methods

TL;DR

This survey reviews smart contract languages emphasizing security features and examines verification tools and methods, highlighting current approaches and future research directions to enhance smart contract safety.

Contribution

It provides a comprehensive overview of smart contract languages and verification methods, and discusses future research directions for improving smart contract security.

Findings

Overview of smart contract languages focusing on security features

Analysis of verification tools and their approaches

Identification of future research directions in formal semantics and automated verification

Abstract

With a market capitalisation of over USD 205 billion in just under ten years, public distributed ledgers have experienced significant adoption. Apart from novel consensus mechanisms, their success is also accountable to smart contracts. These programs allow distrusting parties to enter agreements that are executed autonomously. However, implementation issues in smart contracts caused severe losses to the users of such contracts. Significant efforts are taken to improve their security by introducing new programming languages and advance verification methods. We provide a survey of those efforts in two parts. First, we introduce several smart contract languages focussing on security features. To that end, we present an overview concerning paradigm, type, instruction set, semantics, and metering. Second, we examine verification tools and methods for smart contract and distributed ledgers. Accordingly, we introduce their verification approach, level of automation, coverage, and supported languages. Last, we present future research directions including formal semantics, verified compilers, and automated verification.