An empirical analysis of smart contracts: platforms, applications, and design patterns (1703.06322v1)

Abstract: Smart contracts are computer programs that can be consistently executed by a network of mutually distrusting nodes, without the arbitration of a trusted authority. Because of their resilience to tampering, smart contracts are appealing in many scenarios, especially in those which require transfers of money to respect certain agreed rules (like in financial services and in games). Over the last few years many platforms for smart contracts have been proposed, and some of them have been actually implemented and used. We study how the notion of smart contract is interpreted in some of these platforms. Focussing on the two most widespread ones, Bitcoin and Ethereum, we quantify the usage of smart contracts in relation to their application domain. We also analyse the most common programming patterns in Ethereum, where the source code of smart contracts is available.

• The paper empirically analyzes smart contract platforms, classifying applications and design patterns based on data from 834 contracts.
• It compares Bitcoin's limited scripting with Ethereum’s Turing-complete language, highlighting distinct usage and security implications.
• The study identifies prevalent design patterns like Token and Authorization, offering actionable insights for enhancing blockchain robustness.

Empirical Analysis of Smart Contracts: Platforms, Applications, and Design Patterns

The paper presented by Bartoletti and Pompianu provides a comprehensive examination of smart contracts, focusing primarily on the platforms of Bitcoin and Ethereum, which have become two of the most widespread systems enabling these contracts. Through empirical analysis, the research offers valuable insights into the usage, design, and technological underpinnings of smart contracts across various platforms.

Platforms for Smart Contracts

The paper begins with an evaluation of six platforms: Bitcoin, Ethereum, Counterparty, Stellar, Monax, and Lisk. Key aspects such as blockchain utilization, consensus mechanisms, and the programming language used for smart contracts are compared. The analysis identifies that while Bitcoin and Ethereum are supported by public blockchains, Counterparty piggybacks on Bitcoin’s blockchain to embed its data. Ethereum’s use of a Turing-complete language for contract scripting, contrasted with Bitcoin's limited scripting capabilities, highlights its versatility for complex applications. Platforms like Stellar and Monax, while differing in consensus protocols, offer insights into different approaches to smart contract execution.

A noteworthy illustration was the proliferation of blockchain-related projects, emphasizing the growth of interest and development in this domain. This proliferation underscores the recognition of blockchains and smart contracts in both industry and government sectors, despite ongoing challenges related to trustworthiness and security.

Classification and Usage Analysis

Central to the paper is the classification of smart contracts across five application domains: Financial, Notary, Game, Wallet, and Library. The research compiles a sample comprising 834 contracts—23 from Bitcoin and 811 from Ethereum—for an analysis that encompasses both qualitative and quantitative aspects.

Financial contracts dominate, with 65.5% of all transactions across platforms. The dense use juxtaposed with notary applications, where the usage is significantly more pronounced within Bitcoin, reveals intriguing platform-specific trends. Ethereum’s substantial diversity includes a significant proportion of game-related contracts—7.7% of its contracts are games compared to Bitcoin, which has none—reflecting Ethereum’s more extensive support for complex programming tasks.

Ethereum Design Patterns

An exploration of Ethereum-specific design patterns delineates common architectural constructs in smart contract development. Nine design patterns, including Token, Authorization, and Oracle, are discussed, providing structural insights into Ethereum contracts chiefly utilized for financial services, gaming, and notary functions.

Particularly, the Token pattern is prevalent in financial contracts, indicating Ethereum's function as an issuer for digital assets and shares. The Authorization pattern, used extensively across categories, ensures secure access control, while Oracles are predominantly used in game contracts for external data access. The research reveals that design patterns such as time constraints and termination are universal across different types of contracts.

Implications and Future Directions

The empirical insights provided by Bartoletti and Pompianu's paper have substantial implications for the development of domain-specific languages tailored to smart contracts. Understanding prevalent application domains and their associated design requirements can drive the refinement of smart contract platforms toward increased robustness and security.

The detailed correlation between contract categories and design patterns offers a foundation for targeted improvements in the analytical techniques applied to smart contracts, potentially enhancing the detection and mitigation of vulnerabilities. Furthermore, the survey generates avenues for future research on optimizing smart contract design to facilitate more secure and efficient applications across sectors.

This research marks a significant advancement in the systematic understanding of smart contract ecosystems, offering a robust empirical basis for ongoing developments in blockchain technology.