ETSI GS PDL 033 V1.1.1 (2025-06)

Permissioned Distributed Ledger (PDL); Smart Contracts; System Architecture and Functional Specification

DGS/PDL-0033_Smart_contract

General Information

• Status: Not Published
• Technical Committee: PDL - Permissioned Distributed Ledger
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Due Date: 30-Jun-2025
• Completion Date: 17-Jun-2025

Standards Content (Sample)

GROUP SPECIFICATION
Permissioned Distributed Ledger (PDL);
Smart Contracts;
System Architecture and Functional Specification
Disclaimer
The present document has been produced and approved by the Permissioned Distributed Ledger (PDL) ETSI Industry
Specification Group (ISG) and represents the views of those members who participated in this ISG.
It does not necessarily represent the views of the entire ETSI membership.

2 ETSI GS PDL 033 V1.1.1 (2025-06)

Reference
DGS/PDL-0033_Smart_contract
Keywords
blockchain, PDL, policies, SLA, smart contract

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3 ETSI GS PDL 033 V1.1.1 (2025-06)
Contents
Intellectual Property Rights . 11
Foreword . 11
Modal verbs terminology . 11
Executive summary . 11
Introduction . 12
1 Scope . 13
2 References . 13
2.1 Normative references . 13
2.2 Informative references . 22
3 Definition of terms, symbols and abbreviations . 24
3.1 Terms . 24
3.2 Symbols . 25
3.3 Abbreviations . 25
4 Introduction to Smart Contracts . 26
4.1 Introduction . 26
4.2 Object-Oriented Paradigm . 27
4.2.1 Introduction to OOP in Smart Contracts . 27
4.2.2 Key OOP Concepts in Smart Contracts . 27
4.2.2.1 Encapsulation . 27
4.2.2.2 State and Behaviour . 27
4.2.2.2.1 State . 27
4.2.2.2.2 Behaviour . 28
4.2.2.3 Instantiation . 29
4.2.2.4 Inheritance and Composition . 29
4.2.2.5 Polymorphism . 30
4.2.2.6 Visibility and Access Control . 30
4.2.2.7 Events . 30
4.2.3 Benefits of OOP in Smart Contracts . 31
4.2.4 Considerations for OOP in Distributed Environments . 32
4.2.4.1 Defining the major considerations . 32
4.2.4.2 Gas costs . 32
4.2.4.3 Public nature of blockchain data . 33
4.2.4.4 Consensus mechanisms of the underlying distributed ledger . 35
4.3 Properties of Smart Contracts . 36
4.3.1 Immutability . 36
4.3.1.1 Definition . 36
4.3.1.2 Implications . 37
4.3.1.3 Challenges . 37
4.3.1.4 Solutions . 37
4.3.2 Transparency . 38
4.3.2.1 Definition . 38
4.3.2.2 Key Aspects . 39
4.3.2.3 Benefits . 39
4.3.2.4 Challenges . 39
4.3.2.5 Balancing Transparency and Privacy . 40
4.3.2.6 Considerations for Implementation . 40
4.3.3 Determinism . 41
4.3.3.1 Definition . 41
4.3.3.2 Key Aspects of Determinism . 41
4.3.3.3 Importance of Determinism . 41
4.3.3.4 Challenges associated with Determinism . 42
4.3.3.5 Determinism Implementation Considerations . 42
4.3.3.6 Balancing Determinism and Functionality . 42
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4.3.3.7 Requirements and Recommendations . 42
4.3.4 Atomicity . 43
4.3.4.1 Definition . 43
4.3.4.2 Key Aspects of Atomicity . 43
4.3.4.3 Importance of Atomicity . 44
4.3.4.4 Atomicity Implementation Mechanisms . 45
4.3.4.5 Challenges of Atomicity . 45
4.3.4.6 Atomicity Best Practices . 46
4.3.4.7 Atomicity in Multi-Contract Interactions . 47
4.3.4.8 Requirements and Recommendations . 47
4.3.5 Autonomy . 48
4.3.5.1 Definition . 48
4.3.5.2 Key Aspects of Autonomy . 48
4.3.5.3 Importance of Autonomy . 49
4.3.5.4 Autonomy Implementation Considerations . 50
4.3.5.5 Challenges Associated with Autonomy . 50
4.3.5.6 Balancing Autonomy and Control . 51
4.3.5.7 Autonomy in Different Contexts . 52
4.3.5.8 Best Practices for Implementing Autonomy in Smart Contracts . 52
4.3.5.9 Requirements and Recommendations . 53
4.3.6 Decentralization . 54
4.3.6.1 Definition . 54
4.3.6.2 Key Aspects of Decentralization . 54
4.3.6.3 Importance of Decentralization . 54
4.3.6.4 Decentralization Implementation Considerations . 55
4.3.6.5 Challenges associated with Decentralization . 55
4.3.6.6 Degrees of Decentralization . 55
4.3.6.7 Decentralization in Different Conte xts . 55
4.3.6.8 Best Practices of Decentralization . 56
4.3.6.9 Requirements and Recommendations . 56
4.3.7 State Management . 57
4.3.7.1 Definition . 57
4.3.7.2 Key Aspects of State Management . 57
4.3.7.3 Importance of State Management . 57
4.3.7.4 State Management Implementation Considerations . 58
4.3.7.5 Challenges associated with State Management . 58
4.3.7.6 State Management Patterns . 58
4.3.7.7 Advanced State Management Techniques . 58
4.3.7.8 State Management Best Practices . 59
4.3.7.9 Requirements and Recommendations . 59
4.3.8 Interoperability . 60
4.3.8.1 Definition . 60
4.3.8.2 Key Aspects of Interoperability . 61
4.3.8.3 Importance of Interoperability . 61
4.3.8.4 Interoperability Implementation Mechanisms . 62
4.3.8.5 Challenges associated with Interoperability . 62
4.3.8.6 Interoperability Levels . 62
4.3.8.7 Emerging Interoperability Solutions . 62
4.3.8.8 Best Practices when Implementing Interoperability . 63
4.3.8.9 Requirements and Recommendations . 63
4.3.9 Threats and Security . 64
4.3.9.1 Security Aspects of Smart Contracts . 64
4.3.9.2 Key Aspects . 65
4.3.9.3 Common Vulnerabilities and Attacks . 66
4.3.9.3.1 Introduction . 66
4.3.9.3.2 Internal Threats . 67
4.3.9.3.3 Smart Contract Programming Errors . 67
4.3.9.3.4 External Threats. 68
4.3.9.4 Advanced Smart Contract Security . 68
4.3.9.5 Security Best Practices and Culture in Smart Contracts. 69
4.3.9.6 Tools and Techniques . 70
4.3.9.7 Regulatory and Compliance Considerations . 71
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4.3.9.8 Emerging Security Challenges . 71
4.3.9.9 Security by design . 72
4.3.9.9.1 The importance of Security in the design phase of smart contracts . 72
4.3.9.9.2 Access Control . 72
4.3.9.9.3 Input Validation . 72
4.3.9.9.4 Reentrancy Protection . 72
4.3.9.9.5 Gas Limitations and Denial of Service . 73
4.3.9.9.6 Upgradability and Modularity . 73
4.3.9.9.7 Formal Verification . 73
4.3.9.9.8 External Calls and Interactions . 73
4.3.9.9.9 Error Handling . 73
4.3.10 Reusability . 73
4.3.10.1 Definition . 73
4.3.10.2 Key Aspects . 73
4.3.10.3 Importance . 74
4.3.10.4 Implementation Strategies . 74
4.3.10.5 Challenges . 74
4.3.10.6 Best Practices . 74
4.3.10.7 Examples of Reusable Components . 75
4.3.10.8 Future Trends . 75
4.3.10.9 Requirements and Recommendations . 76
4.3.11 Composability and Contract Interactions . 77
4.4 Storage . 77
4.4.1 Introduction. 77
4.4.2 Types of Storage . 78
4.4.2.1 On-Chain Storage . 78
4.4.2.2 Off-Chain Storage . 78
4.4.2.3 Requirements and Recommendations . 78
4.4.3 Storage Mechanisms . 78
4.4.3.1 State Variables . 78
4.4.3.2 Mappings . 79
4.4.3.3 Arrays . 79
4.4.3.4 Structs . 79
4.4.3.5 Requirements and Recommendations . 79
4.4.4 Storage Optimization Techniques . 79
4.4.4.1 General discussion . 79
4.4.4.2 Data Packing . 80
4.4.4.3 Lazy Loading . 80
4.4.4.4 Deletion and Cleanup . 80
4.4.4.5 Requirements and Recommendations . 80
4.4.5 Cost Considerations . 80
4.4.5.1 Gas Costs . 80
4.4.5.2 Storage Refunds . 81
4.4.5.3 Requirements and Recommendations . 81
4.4.6 Storage Data Security . 81
4.4.6.1 Access Control . 81
4.4.6.2 Data Integrity . 82
4.4.6.3 Requirements and Recommendations . 82
4.4.7 Advanced Storage Patterns . 82
4.4.7.1 Architectural Patterns . 82
4.4.7.2 Eternal Storage . 82
4.4.7.3 Commit-Reveal Schemes . 83
4.4.7.4 Merkle Trees . 83
4.4.7.5 Requirements and Recommendations . 83
4.4.8 Challenges and Considerations . 83
4.4.8.1 Scalability. 83
4.4.8.2 Privacy . 85
4.4.8.3 Long-Term Storage . 85
4.4.8.4 Requirements and recommendations. 85
4.4.9 Future Trends . 86
4.4.9.1 Decentralized Storage Solutions . 86
4.4.9.2 Layer-2 Storage Solutions . 86
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4.4.10 Best Practices . 86
4.4.10.1 General Discussion. 86
4.4.10.2 Requirements and Recommendations . 87
4.5 Modern Smart Contract Platforms and Languages . 87
4.5.1 Introduction. 87
4.5.2 Ethereum and Solidity . 87
4.5.3 Polkadot and Ink . 88
4.5.4 Cardano and Plutus . 89
4.5.5 Algorand and TEAL/PyTeal . 89
4.5.6 Cosmos and CosmWasm . 90
4.5.7 Tezos and Michelson/LIGO . 90
4.5.8 Emerging Trends . 91
5 Smart Contracts - Lifecycle phases . 92
5.1 Introduction . 92
5.2 Planning Phase . 92
5.2.1 Description and recent research . 92
5.2.2 Defining the contract's purpose and requirements . 92
5.2.3 Identifying Stakeholders and Their Interactions . 92
5.2.4 Outlining the Contract's Logic and State Variables . 93
5.2.5 Considering Security, Scalability, and Interoperability Needs . 93
5.2.6 Evaluating Governance and Upgrade Models . 93
5.3 Development and Testing Phase . 93
5.3.1 Description and recent research . 93
5.3.2 Writing the contract code in a suitable language . 94
5.3.3 Implementing security best practices and optimizations. 94
5.3.4 Conducting thorough testing . 94
5.3.4.1 Introduction . 94
5.3.4.2 Testing Strategies . 94
5.3.4.3 Generalized Testing Targets. 95
5.3.4.4 Testing Checklist . 96
5.3.4.5 Offline Testing . 96
5.3.4.6 Online Monitoring . 97
5.3.4.7 Property-Based Testing Frameworks . 97
5.3.4.8 Symbolic Execution Tools . 98
5.3.4.9 SMT Solvers for Smart Contracts . 99
5.3.5 Performing code reviews and audits . 99
5.4 Deployment and Execution Phase . 100
5.4.1 Discussion and recent research . 100
5.4.2 Compiling the contract to bytecode . 100
5.4.3 Selecting the appropriate network for deployment . 100
5.4.4 Executing the deployment transaction . 100
5.4.5 Verifying the deployed contract's bytecode . 101
5.4.6 Monitoring the contract's execution and user interactions . 101
5.5 Maintenance, Update and Upgrade Phases . 101
5.5.1 Introduction. 101
5.5.2 Update Situations . 101
5.5.3 Strategies of Updating . 102
5.5.4 Upgrading Through Versioning . 102
5.5.5 Updating Steps . 102
5.5.6 Checklist Before Redeployment . 103
5.5.7 Securely Inactivating Old Contract . 103
5.5.8 Governing the Upgrade of Smart Contracts . 103
5.5.8.1 Discussion and recent research . 103
5.5.8.2 Governance and upgrade models of Smart Contracts . 104
5.5.8.2.1 Similarities and Differences Between Blockchain Platform Governance and Smart Contract
Change Governance . 104
5.5.8.2.2 Similarities . 104
5.5.8.2.3 Differences . 104
5.5.8.2.4 Recommendations for Effective Smart Contract Governance . 105
5.5.8.2.5 Designing upgrade patterns . 106
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5.5.8.2.6 Establishing Processes for Proposing, Voting on, and Implementing Changes in Smart
Contract Change Management . 106
5.5.8.2.7 Balancing upgradability with security and immutability . 107
5.5.8.3 Requirements and Recommendations . 107
5.6 Retirement or Deprecation Phase . 108
5.6.1 Discussion and recent research . 108
5.6.2 Deciding when a contract should be retired . 109
5.6.3 Implementing a graceful shutdown process . 109
5.6.4 Ensuring users are notified and given time to extract assets or data . 109
5.6.5 Potentially deploying a replacement contract . 109
5.7 Requirements and Recommendations . 110
6 Requirements for Designing a Smart Contract . 111
6.1 Smart Contract Facets . 111
6.1.1 Categories of Facets . 111
6.1.2 Foundational Role . 111
6.1.3 Functional Role . 111
6.1.4 Governance Role . 111
6.1.5 Interoperability Role . 112
6.2 Actors . 112
6.2.1 Distinct roles in a smart contract . 112
6.2.2 Contract Developer . 112
6.2.3 Contract Owner . 113
6.2.4 Contract Users . 113
6.2.5 Governance Body . 113
6.2.6 Auditors .
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