Title Page
Abstract
Contents
Chapter 1. Introduction & Background 13
1.1. Overview 13
1.2. Edge Computing 16
1.3. Blockchain 20
1.4. Blockchain Consensus 22
1.4.1. Byzantine Fault Tolerance 22
1.4.2. Collective Signature 25
1.4.3. Proof of Work 26
1.4.4. Proof of Stake 28
1.5. Challenges with Big Data 29
Chapter 2. Literature Review 31
2.1. Blockchain for Big Data 31
2.1.1. Groupchain 33
2.1.2. Direct Acyclic Graph 35
2.2. Data Modifications 38
2.2.1. Logical & External Deletions 39
2.2.2. Selective Deletion Approach 41
2.2.3. Block Deletion Approach 42
2.3. Distributed Storage 44
2.4. Summary 47
Chapter 3. Big Data in Blockchain 50
3.0. Research Goals and Achievements 50
3.1. Overview of Recordchain structure 51
3.2. Shared Storage 55
3.3. Records & Consensus 57
3.4. Forks 62
3.5. Data Nodes 65
3.6. Evaluations 69
3.6.1. Scalability 71
3.6.2. Storage Utilization 73
3.6.3. Performance 75
3.6.4. Shared Storage 77
3.6.5. Shared Storage Analysis 79
3.6.6. Byzantine Nodes 81
Chapter 4. Data Modifications 82
4.0. Research Goals and Achievements 82
4.1. Recordchain overview 83
4.1.1. Block indexing 85
4.1.2. Data modifications: Pre-defined lifetime 87
4.1.3. Data Modifications: Custom deletions 90
4.2. OWT-based Consensus 92
4.2.1. Block structure 95
4.2.2. Optimal Write Technique 97
4.3. Evaluations 101
4.3.1. Workload Setup 103
4.3.2. Workload A Results 105
4.3.3. Workload B Results 107
4.3.4. Workload C Results 109
4.3.5. Workload D Results 111
4.3.6. Random Workload Results 113
4.4. Limitations and Requirements 115
4.5. Supplementary: Deletions on Tangle 118
4.4.1. Data deletions 120
4.4.2. Climb-up Write Technique 123
4.4.3. Theoretical Analysis 126
4.4.4. Evaluations 129
Chapter 5. Security Analysis 131
5.1. Malicious Node Attacks 131
5.2. Single Point Failure 133
5.3. Core Network 138
Chapter 6. Use-Cases and Applications 141
6.1. Connected car network 142
6.2. Smart city network 143
6.3. Distributed social network 144
6.4. Federated learning (Blockchain for AI) 145
Final Words 146
List of Publications 148
References 149
Table 1. Comparison table for related work 47
Table 2. Node specifications 69
Table 3. Shared Storage Comparison 78
Figure 1. Edge computing overview 17
Figure 2. Blockchain architecture 19
Figure 3. Byzantines general problem 22
Figure 4. Collective Signature Consensus in SklCoin 25
Figure 5. Example scenario for PoW consensus 27
Figure 6. Groupchain architecture 33
Figure 7. Tangle structure and network 34
Figure 8. Selective Deletion in Blockchain 40
Figure 9. Block structure in Littichain 42
Figure 10. Interaction with Distributed Storage 44
Figure 11. Recordchain Node Architecture 51
Figure 12. Record Approval Consensus 57
Figure 13. Node interaction with shared storage 65
Figure 14. Propagation latency (90%) 71
Figure 15. Storage usage 73
Figure 16. Throughput 75
Figure 17. Shared storage latency 77
Figure 18. PBFT and RAC fault tolerance 80
Figure 19. Deletion-based Recordchain overview 83
Figure 20. Recordchain block indexing 84
Figure 21. Block creation order 92
Figure 22. Chain structure 95
Figure 23. Block mining with OWT 97
Figure 24. Evaluation workload 103
Figure 25. Workload A results 105
Figure 26. Workload B results 108
Figure 27. Workload C results 109
Figure 28. Workload D results 111
Figure 29. Random Workload results 113
Figure 30. Climb-up Write Technique 121
Figure 31. D-Tangle evaluation results 128