Source-linked AI summary
Blockchain-based Smart Contracts: A Systematic Mapping Study
Maher Alharby, Aad van Moorsel
TL;DR
Smart-contract research lacked a consolidated technical map of current topics, applications and open challenges. The paper conducts a systematic mapping study and extracts 24 papers, finding that about two thirds address smart-contract issues across codifying, security, privacy and performance. It also identifies applications, related topics and research gaps for future studies.
Problem
Technical research on blockchain-based smart contracts needed its current topics, applications and future research gaps identified and mapped.
Method
The study conducts a systematic mapping study of smart-contract research from a technical perspective.
Results
About two thirds of the 24 extracted papers address smart-contract issues, classified as codifying, security, privacy and performance issues.
Takeaways & Limitations
Current research concentrates on identifying and tackling smart-contract issues, while other work proposes applications and studies related topics.
Takeaways & Limitations
Research is limited by a lack of studies on scalability and performance and by concentration on Ethereum rather than other blockchain platforms.
Abstract
from arXiv · showhide
An appealing feature of blockchain technology is smart contracts. A smart contract is executable code that runs on top of the blockchain to facilitate, execute and enforce an agreement between untrusted parties without the involvement of a trusted third party. In this paper, we conduct a systematic mapping study to collect all research that is relevant to smart contracts from a technical perspective. The aim of doing so is to identify current research topics and open challenges for future studies in smart contract research. We extract 24 papers from different scientific databases. The results show that about two thirds of the papers focus on identifying and tackling smart contract issues. Four key issues are identified, namely, codifying, security, privacy and performance issues. The rest of the papers focuses on smart contract applications or other smart contract related topics. Research gaps that need to be addressed in future studies are provided.
1. INTRODUCTION
Blockchain enables untrusted parties to interact without a trusted third party, while smart contracts execute and enforce agreements on-chain. This study maps technical smart-contract research and identifies future research gaps.
- Blockchain supports distributed interaction between untrusted entities without a trusted third party.Centralised systems can introduce security issues and high transaction fees through reliance on intermediaries.
- Smart contracts are executable blockchain code that facilitates, executes and enforces agreements between untrusted parties.They can release digital assets when predefined rules are satisfied.
- Smart contracts support applications including smart properties, e-commerce and music rights management.
- The study uses a systematic mapping methodology to identify technical research topics and challenges in smart contracts.The resulting map is intended to help researchers identify gaps for future studies.
2. BACKGROUND
Blockchain is a replicated transaction database whose append-only structure supports secure interaction without trusted intermediaries. Smart contracts run on blockchain platforms, with capabilities and applications varying across platforms.
- 2.1. Blockchain Technology: Blockchain records transactions in a replicated, shared database and prevents confirmed transactions from being changed or reverted.Blocks reference preceding blocks through cryptographic hashes, supporting transaction integrity and preventing double spending.
- 2.1. Blockchain Technology: Bitcoin provides cryptocurrency transactions but has limited programming capabilities for complex distributed applications.Its stack-based scripting language supports simple logic such as multisignature transactions, but not rich contract logic.
- 2.1. Blockchain Technology: Ethereum extends blockchain use to complex distributed applications through a built-in Turing-complete language.It is described as the most popular blockchain platform for developing smart contracts.
- 2.1. Blockchain Technology: Public blockchains permit anonymous users to join, read, transact and verify blocks, whereas private blockchains restrict participation through permissions.Bitcoin, NXT and Ethereum are examples of public blockchains.
- 2.2. Smart Contracts: Smart contracts automatically execute agreement terms when specified conditions are met and can reduce transaction fees compared with traditional systems.Their state includes contract storage and balance, and deployment makes the code unchangeable.
- 2.2. Smart Contracts: Deterministic smart contracts use no external information, whereas non-deterministic contracts depend on external data feeds or oracles.Weather-dependent execution is given as an example of a non-deterministic contract.
- 2.3. Smart Contract Platforms: NXT provides template-based smart contracts without customized contracts because its scripting language is not Turing-complete.
- 2.4. Smart Contract Applications: Potential applications include smart property, music rights management, e-commerce, identity management, voting, insurance and supply chains.Examples include distributing music payments and releasing e-commerce payment after buyer satisfaction.
3. RESEARCH METHODOLOGY
The study applies a five-step systematic mapping process to identify and classify technical smart-contract research. It defines research questions, searches and screens papers, extracts data, and maps topics using keywords.
- The systematic mapping study follows five steps to identify research areas and gaps related to smart contracts.The process is based on a previously presented systematic mapping methodology.
- Definition of research questions: The study asks which research topics, applications and future research gaps currently exist for smart contracts.
- Searching for relevant papers: The search uses “smart contract” as the main keyword across selected scientific databases.The keyword narrows the review to smart-contract-related work.
- Screening for relevant papers: Screening excludes papers judged irrelevant and papers failing stated criteria such as language or full-text availability.Titles and abstracts are examined when relevance cannot be determined from titles alone.
- Key-wording using abstracts: Key-wording classifies relevant papers using important abstract keywords and main contributions, with later revisions when necessary.
- Data extraction and mapping process: Data extraction gathers information about each paper’s aims and contributions to answer the study’s research questions.
4. STUDY RESULTS
The mapping study groups smart-contract research primarily around codifying, security, privacy, and performance issues, with additional work on applications and related topics. Reported solutions include verification, safer contract standards, optimization tools, privacy-preserving systems, and authenticated data feeds.
- About two thirds of reviewed papers address smart-contract issues, classified as codifying, security, privacy, or performance concerns.
- Codifying issues: Codifying challenges include writing correct contracts, modifying or terminating deployed contracts, detecting under-optimization, and managing complex programming languages.
- Codifying issues: Proposed codifying solutions include semi-automated contract creation, developer guidelines, formal verification, change and termination standards, GASPER, and logic-based languages.
- Security issues: Six security issues include transaction-ordering dependency, timestamp dependency, mishandled exceptions, criminal activities, re-entrancy, and untrustworthy data feeds.
- Security issues: Security mitigations include transaction-order guards, fixed block numbers instead of timestamps, return-value checks, OYENTE detection, and safeguards against criminal activities.
- Privacy and data-feed issues: Privacy research addresses public transaction and balance data, while Town Crier provides authenticated external data feeds for contracts lacking trustworthy oracles.
5. DISCUSSION
The study finds that smart-contract research primarily addresses codifying, security, privacy, and performance issues, while other work examines applications and related topics. It identifies gaps involving scalability, blockchain diversity, applications, criminal activities, and peer-reviewed research quality.
- Current research topics: Most current research identifies and tackles codifying, security, privacy, and performance issues in smart contracts.Codifying and security receive especially substantial attention because coding errors or security breaches can cause monetary losses.
- Applications and related topics: Smart-contract applications include trading, fair exchange, identity management, Internet of Thing, and agreement establishment.Other studies address licensing, scripting languages, consensus methods, and blockchain information indexing.
- Research gaps: The literature lacks studies on scalability and performance, while sequential execution constrains blockchain scaling.Parallel execution is suggested, but existing work provides no concrete evaluation and must address dependent contracts.
- Research gaps: Almost all current research concerns Ethereum, leaving other smart-contract-capable blockchains such as NXT and Eris underexplored.Different blockchains have distinctive features and advantages that future research could investigate.
- Research gaps: The literature contains few smart-contract applications because the concept remains in its infancy and is not widely common in practice.Suggested future application areas include e-commerce and cloud storage.
- Research gaps: Further gaps concern criminal-activity countermeasures and high-quality peer-reviewed research on smart contracts.Existing work identified only three criminal-activity types without proposing solutions, while much research appears as blog articles or grey literature.
6. CONCLUSION
The study maps technical research on blockchain-based smart contracts and identifies gaps for future work. It highlights limited coverage of scalability, performance, alternative blockchain platforms, applications, criminal activities, and research quality.
- Blockchain-based smart contracts enable agreements between untrusted parties without a trusted third party.
- The study used a systematic mapping approach to identify and map technical smart-contract research areas.
- Future studies should address limited research on scalability and performance, deployment beyond Ethereum, and smart-contract applications.
- Additional gaps concern criminal activities in smart contracts and the lack of high-quality smart-contract research.