“I’m still / I’m still / Chaining from the Block”
0 likes55 views
The document provides an overview of blockchain technologies' evolving relationship with process-aware information systems, detailing key concepts such as transactions, ledgers, and smart contracts. It discusses the implications of decentralization, programmability, and traceability in blockchain applications and the role of oracles in bridging on-chain and off-chain interactions. The document emphasizes the necessity of considering costs, privacy, and data integrity within blockchain-enabled processes.
![Centralised ledger
03/06/2024
Claudio Di Ciccio
11
“In Amsterdam, the water bailiff’s office was
located in the […] middle of one of the
seafarers’ quarters […] open for registering
IOUs six days per week.
On one occasion, clerks […] worked
overtime on a Sunday: presumably
because the company of H. Lond, one of
the largest lenders in town, had delivered its
1314 unredeemed IOUs the day before and
they did not want to start the new week with
such a backlog”](https://image.slidesharecdn.com/diciccio-caise-b4tdsbc4is-2024-240606135355-962709b6/85/I-m-still-I-m-still-Chaining-from-the-Block-11-320.jpg)
![“A universal platform with internal
programming language, so that everyone
could write any app”
[V. Buterin]
03/06/2024
14
Claudio
Di
Ciccio
From a peer-to-peer electronic cash system
to a programmable distributed environment](https://image.slidesharecdn.com/diciccio-caise-b4tdsbc4is-2024-240606135355-962709b6/85/I-m-still-I-m-still-Chaining-from-the-Block-14-320.jpg)
![The Oracle
03/06/2024
Claudio Di Ciccio
49
Foundational Oracle Patterns: Connecting Blockchain to the Off-Chain World. BPM (Blockchain and RPA Forum) 2020: 35-51
DB
ISO/TC 307, ISO/TR 2345: “[A] DLT Oracle [is a] service that updates a distributed
ledger using data from outside the distributed ledger system”. (2019)
Previous literature: oracles as off-chain information providers.
We see oracles as a bridge
between the on-chain and off-chain worlds.](https://image.slidesharecdn.com/diciccio-caise-b4tdsbc4is-2024-240606135355-962709b6/85/I-m-still-I-m-still-Chaining-from-the-Block-48-320.jpg)
“I’m still / I’m still / Chaining from the Block”
- 1. “I’m still / I’m still / Chaining from the Block” An Outlook of the Ongoing and Future Relationship between Blockchain Technologies and Process-aware Information Systems Claudio Di Ciccio | https://diciccio.net/ | c.diciccio@uu.nl Utrecht University, Netherlands
- 2. Claudio Di Ciccio Associate professor Ph.D. in Computer Science and Engineering Faculty of Science / Software Division / Process Science Group Main research interests: formal methods & logic and computation, applied in process analytics & blockchain architectures Claudio Di Ciccio 03/06/2024 2
- 3. My experience so far 03/06/2024 Claudio Di Ciccio Latina, Italy (B.Sc) Rome, Italy (M.Sc, Ph.D) Vienna, Austria (Post-doc, Assistant Prof.) Rome, Italy (Assistant Prof., Associate Prof.) Utrecht, Netherlands (Associate Prof.) 3
- 4. Transaction • Transfer of (crypto)assets (Ether, Bitcoin, Algo, …) from account A to account B Externally Owned Account (EOA) Externally Owned Account (EOA) Digital signature 03/06/2024 Claudio Di Ciccio 4 Transaction ID: 0xfa12…40c6da
- 5. Ledger • Ordered collection of transactions • The order matters! 03/06/2024 Claudio Di Ciccio 5
- 6. Amsterdam, 1856 03/06/2024 Claudio Di Ciccio 6 • About 2000 ships departed on an annual basis • Seafarers numerous a vital contribution to trade wages paid after a journey (always in need of credit) • Non-bank credit markets Shopkeepers and boarding-house keepers as lenders • The Discipline Act (1856) Forbids the use of seafarers’ wages as redemption payments Image source: https://www.istockphoto.com/nl/vector/amsterdam-in-the-19th-century-gm538063610-95625387
- 7. The ledger of the water bailiff’s 03/06/2024 Claudio Di Ciccio 7 • The Discipline Act prescribed that lenders had to present their unredeemed IOUs to the water bailiff’s during the month of July 1856 • Every IOU recorded basic information, including: the date on which it was entered the names of lender and borrower the unredeemed amount • 13,708 loans were registered in a 443-page ledger A hand-drawn ink lithography of men writing a ledger in the water bailiff's office in 1856 (DALL-E, https://openai.com/dall-e-2/)
- 8. Block • Blocks group and collate transactions • The order matters! 03/06/2024 Claudio Di Ciccio 8
- 9. Hashing the previous block for immutability • Blocks refer back to direct predecessors via hashing • The order matters! 03/06/2024 Claudio Di Ciccio 9
- 10. The blockchain remembers 03/06/2024 Claudio Di Ciccio 10
- 11. Centralised ledger 03/06/2024 Claudio Di Ciccio 11 “In Amsterdam, the water bailiff’s office was located in the […] middle of one of the seafarers’ quarters […] open for registering IOUs six days per week. On one occasion, clerks […] worked overtime on a Sunday: presumably because the company of H. Lond, one of the largest lenders in town, had delivered its 1314 unredeemed IOUs the day before and they did not want to start the new week with such a backlog”
- 12. Decentralisation for persistence 03/06/2024 Claudio Di Ciccio 12 Centralisation Decentralisation Warning: possible information inconsistency → proof-of-* and consensus
- 13. Private|public / Permissioned|permissionless Transactability / visibility Private Public Consensus Permissionless Selected nodes can transact and view, every node can participate in consensus Every node can transact and view and participate in consensus Permissioned Selected nodes can transact and view, a subset of which can participate in consensus Every node can transact and view, selected nodes participate in consensus 03/06/2024 Claudio Di Ciccio Anderberg et al. “Blockchain Now And Tomorrow” (2019) http://dx.doi.org/10.2760/901029 13
- 14. “A universal platform with internal programming language, so that everyone could write any app” [V. Buterin] 03/06/2024 14 Claudio Di Ciccio From a peer-to-peer electronic cash system to a programmable distributed environment
- 15. Smart Contracts 03/06/2024 Claudio Di Ciccio 15 • Smart Contracts in Ethereum live in the Ethereum environment execute a function when called have direct control over their own balance and key/value storage exhibit a behaviour that is fully specified by their code
- 16. Expressive power of smart contracts 03/06/2024 Claudio Di Ciccio 16 • Variants exist • Solidity is a Turing-complete language for the Ethereum blockchain • Smart contracts can potentially run any computable algorithm Picture: https://doi.org/10.1093/ref:odnb/36578
- 17. A programmable distributed environment Input encoded data Smart Contract Account 03/06/2024 Claudio Di Ciccio 17 Invoking a smart contract function Execution is not externally stoppable!
- 18. From high-level code to bytecode to bits and bytes 03/06/2024 Claudio Di Ciccio 18
- 19. A programmable distributed environment Input encoded data. Smart Contract Account 03/06/2024 Claudio Di Ciccio 19 New Smart Contract Account New address Smart contract code to be deployed Invoking a smart contract function Deploying a new smart contract Execution is not externally stoppable!
- 20. 03/06/2024 Claudio Di Ciccio 20 Where are Smart Contracts executed? First on the mining nodes. Then, potentially, on every node! The polygraph machine
- 21. A programmable distributed environment Input encoded data. Smart Contract Account 03/06/2024 Claudio Di Ciccio 21 New Smart Contract Account New address Smart contract code to be deployed Invoking a smart contract function Deploying a new smart contract Execution is not externally stoppable! Gas price (execution costs) Gas price (execution costs)
- 22. Execution is not for free (most of all, in public blockchains) 03/06/2024 Claudio Di Ciccio 22 Wood , “Ethereum: A secure decentralised generalised transaction ledger” (2014), https://ethereum.github.com/yellowpaper/paper.pdf
- 23. Challenges about costs 03/06/2024 Claudio Di Ciccio 23
- 24. Price instability of cryptocurrency and gas prices 03/06/2024 Claudio Di Ciccio 24 ETH/EUR exchange Gas price on the Ropsten testnet
- 25. Cryptos and fiat money 03/06/2024 Claudio Di Ciccio 25 Image source: https://www.kbrillphotograp.top/products.aspx?cname=jlo+jenny+from+the+block+outfit&cid=140 Keep smart contracts lean! Only absolutely needed instructions should be in the code.
- 26. The paradigm Mainframe Terminal 03/06/2024 Claudio Di Ciccio 26 L: https://commons.wikimedia.org/wiki/File:SiemensHicom300_1200.jpg; R: https://commons.wikimedia.org/wiki/File:HP_2647A_terminal.jpg
- 27. Web 3.0 and Decentralised applications (DApps) 27 03/06/2024 Claudio Di Ciccio
- 28. Advantages and connection to processes • Smart contracts → Programmability → Process rule enforcing • Transactions → Asset transfer & function invocation → Process execution • Distributed store → Data persistency → Process monitoring • Ledger → Transaction ordering → Logging • Hashing → Robustness → Secure storage • Signatures → Authentication → Non-repudiability • Consensus → Eventual consistency → Traceability 03/06/2024 Claudio Di Ciccio 28 Images: Left: https://doi.org/10.1145/3183367; right: https://www.dagstuhl.de/en/seminars/seminar-calendar/seminar-details/18332 Layer of trust even in a regime of partial trust among actors
- 29. Executing inter-organisational processes on the Blockchain: A model-driven approach D.C, Cecconi, A., Dumas, M., et al. (2019), “Blockchain support for collaborative business processes” 03/06/2024 Claudio Di Ciccio 29
- 30. Executing inter-organisational processes on the Blockchain: A model-driven approach Caterpillar Lorikeet 03/06/2024 Claudio Di Ciccio 30 ChorChain D.C, Cecconi, Dumas et al. Blockchain support for collaborative business processes. Informatik Spektrum pp. 1–9 (May 2019) López-Pintado, García-Bañuelos, Dumas, Weber. Caterpillar: A blockchain-based business process management system. In: BPM Demos. CEUR.ws, 2017. Tran, Lu, Weber. Lorikeet: A Model-Driven Engineering Tool for Blockchain-Based Business Process Execution and Asset. In: BPM Demos. CEUR.ws, 2018. Corradini, Marcelletti, Morichetta, Polini, Re, Tiezzi: Engineering Trustable and Auditable Choreography-based Systems Using Blockchain. ACM TMIS 13(3), 2022.
- 31. Tracking execution 03/06/2024 Claudio Di Ciccio D.C. et al. Blockchain-Based Traceability of Inter-organisational Business Processes. In: BMSD. Springer, 2018. 31
- 32. Traceability 03/06/2024 Claudio Di Ciccio 32 D.C. et al. Blockchain-Based Traceability of Inter-organisational Business Processes. In: BMSD. Springer, 2018.
- 33. From execution to ledgers 03/06/2024 34 Claudio Di Ciccio
- 34. Traceability 03/06/2024 Claudio Di Ciccio 35 https://www.sage.com/en-gb/blog/blockchain-traceability-supply-chain/ Accessed: 19/02/2020
- 35. From ledgers to time-ordered datasets 03/06/2024 Claudio Di Ciccio 36
- 36. From data sets to process mining and analytics 03/06/2024 Claudio Di Ciccio 37
- 37. Mining blockchain processes 03/06/2024 Claudio Di Ciccio 38
- 38. Mining blockchain processes 03/06/2024 Claudio Di Ciccio 39
- 39. Double spending 03/06/2024 Claudio Di Ciccio 40 0xA 0xB 0xC 100 ¢ 10 ¢ 50 ¢ 10 ¢ 140 ¢ 90 ¢ 50 ¢ Tx ID: 0xA90B Tx ID: 0xA50C X
- 40. Double spending 41 03/06/2024 Claudio Di Ciccio 0xA 0xB 0xC 100 ¢ 10 ¢ 50 ¢ 90 ¢ Tx ID: 0xA90B 50 ¢ Tx ID: 0xA50C
- 41. Double spending 42 03/06/2024 Claudio Di Ciccio 0xA 0xB 0xC 100 ¢ 10 ¢ 50 ¢ 90 ¢ Tx ID: 0xA90B 50 ¢ Tx ID: 0xA50C 60 ¢ 50 ¢ X
- 42. On-chain vs off-chain 03/06/2024 Claudio Di Ciccio 43 Image source: https://www.kbrillphotograp.top/products.aspx?cname=jlo+jenny+from+the+block+outfit&cid=140 The broken link is that blockchain natively has no control on or view of off-chain objects
- 43. The problem 03/06/2024 Claudio Di Ciccio 44 DB
- 44. How about the real world? Oracles: From on-chain to off-chain and vice versa 03/06/2024 45 Claudio Di Ciccio
- 45. The Oracle 03/06/2024 Claudio Di Ciccio 46 Foundational Oracle Patterns: Connecting Blockchain to the Off-Chain World. BPM (Blockchain and RPA Forum) 2020: 35-51 DB
- 47. Flight delay insurance: the FlightDelayPayout contract 03/06/2024 Claudio Di Ciccio 48 Payout in case of signalled problems with the flight Contact with the off-chain world Source: https://www.flickr.com/photos/michaelduxbury/5824469025
- 48. The Oracle 03/06/2024 Claudio Di Ciccio 49 Foundational Oracle Patterns: Connecting Blockchain to the Off-Chain World. BPM (Blockchain and RPA Forum) 2020: 35-51 DB ISO/TC 307, ISO/TR 2345: “[A] DLT Oracle [is a] service that updates a distributed ledger using data from outside the distributed ledger system”. (2019) Previous literature: oracles as off-chain information providers. We see oracles as a bridge between the on-chain and off-chain worlds.
- 49. Oracle patterns: Overview 03/06/2024 Claudio Di Ciccio Foundational Oracle Patterns: Connecting Blockchain to the Off-Chain World. BPM (Blockchain and RPA Forum) 2020: 35-51 50
- 50. Decentralised oracles 03/06/2024 Claudio Di Ciccio Enhancing Blockchain-Based Processes with Decentralized Oracles. In: BPM Blockchain and RPA Forum 2021, 102-118, Springer. 51
- 51. Decentralised oracles (example: pull-in) 03/06/2024 Claudio Di Ciccio Enhancing Blockchain-Based Processes with Decentralized Oracles. In: BPM Blockchain and RPA Forum 2021, 102-118, Springer. 52
- 52. Decentralised oracles (example: pull-in) 03/06/2024 Claudio Di Ciccio 53 Enhancing Blockchain-Based Processes with Decentralized Oracles. In: BPM Blockchain and RPA Forum 2021, 102-118, Springer. Credit institute 1 Decentralized oracle Credit institute 3 Credit institute 2 Smart contract
- 53. About privity • Albeit very costly, we could inject all the information we need on-chain. • Even if we were able to inject all the data in the world on chain, would we like the idea? • “Privity strives for limiting the sharing of information within a contract to those parties of a contract who have a contractual need to know” 03/06/2024 Claudio Di Ciccio 54 Köpke, Franceschetti, Eder: Balancing Privity and Enforceability of BPM-Based Smart Contracts on Blockchains. BPM (Blockchain and CEE Forum) 2019: 87-102
- 54. While collaborators cooperate… 03/06/2024 Claudio Di Ciccio 55 Signing of the Peace Protocol Between Spain and the United States, August 12, 1898 (source: https://library.whitehousehistory.org/fotoweb/archives/5017-Digital-Library/Main%20Index/Artwork/520.tif.info)
- 55. … the whole network observes 03/06/2024 Claudio Di Ciccio 56 Scene from The Truman Show (1998). Image source: https://redeemingculture.com/film/drama/4106-the-truman-show-empathy-and-reality
- 56. Ledger and secrecy 03/06/2024 Claudio Di Ciccio 57 Image source: https://www.kbrillphotograp.top/products.aspx?cname=jlo+jenny+from+the+block+outfit&cid=140 Every participant in the blockchain network can read the data on the ledger unless the platform is private and permissioned Public permissionless platforms are more robust and guarantee non- repudiability
- 57. Transaction information hiding via homomorphic encryption 03/06/2024 Claudio Di Ciccio Xu, Zhang, Zhu (2023). Regulation-Friendly Privacy-Preserving Blockchain Based on zk-SNARK. In: Advanced Information Systems Engineering Workshops. CAiSE 2023 58 Coming next: High-Performance Confidentially-Preserving Blockchain via GPU-Accelerated Fully Homomorphic Encryption (Guan, Qi, Shen, Wang, Zhang and Cui)
- 58. Fix this image in your memory 03/06/2024 Claudio Di Ciccio Image source: https://www.makinggameofthrones.com/production-diary/2013/5/29/leeches-dragons-and-a-bear-behind-the-scenes-of-episodes-307.html 59
- 59. Is this the same image? 03/06/2024 Claudio Di Ciccio Image source: https://www.makinggameofthrones.com/production-diary/2013/5/29/leeches-dragons-and-a-bear-behind-the-scenes-of-episodes-307.html 60
- 60. Validation v. understanding 03/06/2024 Claudio Di Ciccio 61 Image source: https://www.makinggameofthrones.com/production-diary/2013/5/29/leeches-dragons-and-a-bear-behind-the-scenes-of-episodes-307.html
- 61. Business Process Model and Notation (BPMN) collaboration diagram 03/06/2024 Claudio Di Ciccio 62 anufacturer Production order set up Order parts ill of materials echanical parts supplier ill of materials received Electronic parts supplier ill of materials received
- 62. The message, in clear (as seen by the manufacturer) 03/06/2024 Claudio Di Ciccio 63 0xfd9ffe3578a42d81c4684bd47e6575d9a8f10cc6dab984bd7e19ee0dbacb6287 Hash:
- 63. The message (as seen by external parties) 03/06/2024 Claudio Di Ciccio 64 0xfd9ffe3578a42d81c4684bd47e6575d9a8f10cc6dab984bd7e19ee0dbacb6287 Hash:
- 64. The message (as seen by the electronic parts supplier) 03/06/2024 Claudio Di Ciccio 65 0xfd9ffe3578a42d81c4684bd47e6575d9a8f10cc6dab984bd7e19ee0dbacb6287 Hash:
- 65. The message (as seen by the mechanical parts supplier) 03/06/2024 Claudio Di Ciccio 66 0xfd9ffe3578a42d81c4684bd47e6575d9a8f10cc6dab984bd7e19ee0dbacb6287 Hash:
- 66. Hence the name: CAKE 03/06/2024 Claudio Di Ciccio 67 Image source: https://heriots.co.uk/products/pistachio Thursday, June 6, 14:00: CAKE: Sharing Slices of Confidential Data on Blockchain (Maragone, Spina, D.C., Weber)
- 67. Ingredients • Blockchain platform • Smart contracts • InterPlanetary File System (IPFS) • Ciphertext-Policy (CP) Attribute-Based Encryption (ABE) 03/06/2024 Claudio Di Ciccio 68
- 68. CP-ABE • Attribute-Based Encryption (ABE): type of public-key encryption • Ciphertext-Policy ABE (CP): We associate roles and process instance ID with attributes (propositional literals) Messages are associated with policies (propositional formulae on attributes) • Attributes: 14548487, Supplier, Electronics, Mechanics, Manufacturer • Policy: 14548487 AND (Manufacturer OR (Supplier AND Electronics)) 03/06/2024 Claudio Di Ciccio 69 Process instance ID Roles
- 69. CAKE 03/06/2024 Claudio Di Ciccio 70 Icons: https://www.iconfinder.com/ Policy Plaintext Ciphertext Ciphertext Plaintext Secret key Attributes Secret key 1: ciphering 2: key generation 3: deciphering 0: pre-phase Public key (pk) Master public key (mpk) pk pk Key pair Key pair pk mpk Given Attribute certification
- 70. Phase 0: certification 03/06/2024 Claudio Di Ciccio 71 Attribute certifier Address: 0x123 Attributes: 14548487, Manufacturer Address: 0x456 Attributes: 14548487, Supplier, Electronics Address: 0x789 Attributes: 14548487, Supplier, Mechanics Smart Contract
- 71. Phase 1: ciphering 03/06/2024 Claudio Di Ciccio 72
- 72. Phase 1: ciphering 03/06/2024 Claudio Di Ciccio 73
- 73. Phase 2: key generation 03/06/2024 Claudio Di Ciccio 74 14548487, Manufacturer 14548487, Supplier, Electronics 14548487, Supplier, Mechanics D: 2nN6…GCcZ Dj: 4558…5+Qg Djp: 8944….5949 D: A9BS…CnoO Dj: OQEL…1207 Djp: hI2M…. lWBb D: 1+8Ka…kaUd Dj: feoH…7393 Djp: bJju…. NIGw Key pair Key pair Key pair
- 74. Message policy example 03/06/2024 Claudio Di Ciccio 75 Attributes Process instance (case id)
- 75. Phase 3: deciphering 03/06/2024 Claudio Di Ciccio 76
- 76. Phase 3: deciphering 03/06/2024 Claudio Di Ciccio 77
- 77. Focus 03/06/2024 Claudio Di Ciccio 78 14548487, Supplier, Mechanics Why?
- 78. Q&A • Why a certifier? With signatures, you can prove that “you are you” Without a certifier, you cannot prove that what you say is true • Who forges the keys? A delegated key manager • One certifier, one key manager. What about decentralisation? Right… • Can you integrate your technique with a BPMS? Not yet but… 03/06/2024 Claudio Di Ciccio Marangone, D.C:, Weber: Fine-Grained Data Access Control for Collaborative Process Execution on Blockchain. BPM (Blockchain and RPA Forum) 2022: 51-67 79
- 79. Room for improvement 03/06/2024 Claudio Di Ciccio Marangone, D.C., Friolo, Nemmi, Venturi, Weber: MARTSIA: Enabling Data Confidentiality for Blockchain-based Process Execution (2023) 80 Multi-Authority Approach to Transaction Systems for Interoperating Applications
- 80. The new architecture: MARTSIA 03/06/2024 Claudio Di Ciccio Marangone, D.C., Friolo, Nemmi, Venturi, Weber: MARTSIA: Enabling Data Confidentiality for Blockchain-based Process Execution (2023) 81 1. Key management 2. Data exchange 0. Initialisation Push- inbound oracle Pull- outbound oracle
- 81. Integration with Caterpillar 03/06/2024 Claudio Di Ciccio 82
- 82. About the costs 03/06/2024 Claudio Di Ciccio 83
- 83. Why are prices in Gwei? 03/06/2024 Claudio Di Ciccio 84 ETH/EUR exchange Gas price on the Ropsten testnet
- 84. Open challenges • Revoke access to data • Let Smart Contracts use off-chain data via pull-inbound oracles • Test with real-world multi-party business processes in production • Extend the policy language with primitives for aggregating and manipulating data • … 03/06/2024 Claudio Di Ciccio 85 Friday, June 7, 14:00: Trusted Execution Environment for Decentralized Process Mining (Goretti, Basile, Barbaro, D.C.)
- 85. Open challenges at large • Strike a balance between “smart-contracting” and off-chain deployment of PAISs • Define the interplay of Blockchain-as-a-Service for PAISs • Build a standard communication format for blockchain-based inter- organisational information exchange • Establish guidelines for the use of blockchain technologies with and within PAISs • … 03/06/2024 Claudio Di Ciccio 86 Friday, June 7, 14:00: Trusted Execution Environment for Decentralized Process Mining (Goretti, Basile, Barbaro, D.C.)
- 86. “I’m still / I’m still / Chaining from the Block” An Outlook of the Ongoing and Future Relationship between Blockchain Technologies and Process-aware Information Systems Claudio Di Ciccio | https://diciccio.net/ | c.diciccio@uu.nl Utrecht University, Netherlands Picture: https://youtu.be/dly6p4Fu5TE?si=MTqzSi5KGLIZn3sr Friday, June 7, 14:00: Trusted Execution Environment for Decentralized Process Mining (Goretti, Basile, Barbaro, D.C.)