Blockchain and smart contracts: infrastructure and platforms
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The document presents an overview of blockchain technology and smart contracts as infrastructures for decentralized transactions and processes. It discusses the structure of blockchains, the function of smart contracts as autonomous code executing within these platforms, and the significance of oracles in linking on-chain and off-chain data. The content is geared towards providing foundational knowledge and insights into the applications and challenges of blockchain in various domains.
![From peer-to-peer electronic cash system
to programmable distributed environment
“A universal platform with internal programming language, so that
everyone could write any app”
[V. Buterin]
C.
Di
Ciccio,
March
2021
Blockchain
and
smart
contracts
20](https://image.slidesharecdn.com/diciccio-cyber4-210304103532/85/Blockchain-and-smart-contracts-infrastructure-and-platforms-20-320.jpg)
![Systems like to report on their job (logging)
• [2019-02-18T12:30:00-02:00] 0xACDC0801 executes Draw Out
Wire on Item 0xAA01
• [2019-02-18T12:30:10-02:00] 0xACDC0802 executes Straight
Wire on Item 0xAA01
• [2019-02-18T12:30:20-02:00] 0xACDC0803 executes Cut Wire on
Item 0xAA01
• [2019-02-18T12:30:30-02:00] 0xACDC0801 executes Draw Out
Wire on Item 0xAA02
• [2019-02-18T12:30:40-02:00] 0xACDC0802 executes Straight
Wire on Item 0xAA02
• [2019-02-18T12:30:50-02:00] 0xACDC0804 executes Point Wire
on Item 0xAA01
• [2019-02-18T12:31:00-02:00] 0xACDC0801 executes Draw Out
Wire on Item 0xAA03
• …
Icons © freepik.com
C.
Di
Ciccio,
March
2021
Blockchain
and
smart
contracts
38](https://image.slidesharecdn.com/diciccio-cyber4-210304103532/85/Blockchain-and-smart-contracts-infrastructure-and-platforms-38-320.jpg)
![The Oracle
C.
Di
Ciccio,
March
2021
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.
Blockchain
and
smart
contracts
51](https://image.slidesharecdn.com/diciccio-cyber4-210304103532/85/Blockchain-and-smart-contracts-infrastructure-and-platforms-51-320.jpg)
Blockchain and smart contracts: infrastructure and platforms
- 1. Blockchain and smart contracts: infrastructure and platforms Claudio Di Ciccio | http://diciccio.net | [email protected] Sapienza, University of Rome, Italy Cyber 4.0 Seminar, 2021, March the 3rd
- 2. Claudio Di Ciccio Assistant professor Ph.D. in Computer Science and Engineering Main researchinterests: process mining, blockchains, declarative process modelling, service-orientedarchitectures C. Di Ciccio, March 2021 Blockchain and smart contracts 2
- 3. My experience so far C. Di Ciccio, March 2021 Latina, Italy (B.Sc) Rome, Italy (M.Sc, Ph.D) Vienna, Austria (Post-doc, Assistant Prof .) Rome, Italy (Assistant Prof .) Blockchain and smart contracts 3
- 4. Half empty or half full? http://aeon.co/ideas/which-is-more-fundamental-processes-or-things C. Di Ciccio, March 2021 Blockchain and smart contracts 4
- 5. Processes are into dynamics Thanks Dr. Mieke Jans for offering her hand C. Di Ciccio, March 2021 Blockchain and smart contracts 5
- 7. Transaction • Transfer of (crypto)assets (Ether, Bitcoin, Litecoin, EOS, …) from account A to account B Externally Owned Account (EOA) Externally Owned Account (EOA) Digital signature C. Di Ciccio, March 2021 Blockchain and smart contracts 7
- 8. Ledger • Ordered collection of transactions • The order matters! C. Di Ciccio, March 2021 Blockchain and smart contracts 8
- 9. Block • Blocks group and collate transactions • The order matters! C. Di Ciccio, March 2021 Blockchain and smart contracts 9
- 10. Hashing the previous block for immutability • Blocks refer back to direct predecessors • The order matters! C. Di Ciccio, March 2021 Blockchain and smart contracts 10
- 12. Ledgers • A ledger is a collection of transactions. Throughout history, on paper; recently, stored digitally • Shortcomings of centralised ledgers: They may be lost or destroyed: a user must trust that the owner is properly backing up the system Transactions may not be valid: a user must trust that the owner is validating each received transaction The transaction list may not be complete: a user must trust that the owner is including all valid transactions that have been received The transaction data may have been altered: a user must trust that the owner is not altering past transactions C. Di Ciccio, March 2021 Blockchain and smart contracts 12
- 13. Decentralisation for persistence Centralisation Decentralisation Distributing the ledger makes for permanence BUT entails no notion of unique distributed clock C. Di Ciccio, March 2021 Blockchain and smart contracts 13
- 17. Mining for a blockchain Proof of Work (PoW): obtain the right to publish the next block by solving a computationally intensive puzzle Checking that a solution is valid is easy Solving the puzzle is difficult: an incentive is needed C. Di Ciccio, March 2021 Blockchain and smart contracts 17
- 18. Ledgers are distributed and maintained by a network https://ehtstats.net https://ehternodes.org C. Di Ciccio, March 2021 Blockchain and smart contracts 18
- 20. From peer-to-peer electronic cash system to programmable distributed environment “A universal platform with internal programming language, so that everyone could write any app” [V. Buterin] C. Di Ciccio, March 2021 Blockchain and smart contracts 20
- 21. Smart Contracts are codified autonomous agents C. Di Ciccio, March 2021 Blockchain and smart contracts 21
- 22. Smart Contracts are pieces of code C. Di Ciccio, March 2021 Blockchain and smart contracts 22
- 23. Smart Contracts are pieces of code • 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 have their behaviour fully specified by their code C. Di Ciccio, March 2021 Blockchain and smart contracts 23
- 24. The polygraph machine Where are Smart Contracts executed? First on the mining nodes. Then, potentially, on every node! Only absolutely needed instructions should be put in code! C. Di Ciccio, March 2021 Blockchain and smart contracts 24
- 25. A programmable distributed environment Gas price (execution costs) Input (and output) encoded data. Smart Contract Account C. Di Ciccio, March 2021 Blockchain and smart contracts 25 New Smart Contract Account New address Smart contract code to be deployed Invoking a smart contract function Deploying a new smart contract
- 27. Smart Contracts are pieces of code (not for free) Wood 2014 C. Di Ciccio, March 2021 Blockchain and smart contracts 27
- 28. Tokens are not cryptofuel Nothing specific of blockchains, after all! 1:5 C. Di Ciccio, March 2021 Blockchain and smart contracts 28
- 29. Your brand new token in 5 minutes or less C. Di Ciccio, March 2021 Blockchain and smart contracts 29
- 32. The Blockchain and the Internet 32 C. Di Ciccio, March 2021 Blockchain and smart contracts
- 33. Web 1.0 33 Back end Front end C. Di Ciccio, March 2021 Blockchain and smart contracts
- 36. Blockchain as a process execution infrastructure C. Di Ciccio, March 2021 Blockchain and smart contracts 36
- 37. Division of labour → Automation Draw out wire Straight wire Cut wire Grind wire Put head on pin Put pin in paper Whiten pin Point wire Make head Icons © freepik.com C. Di Ciccio, March 2021 Blockchain and smart contracts 37
- 38. Systems like to report on their job (logging) • [2019-02-18T12:30:00-02:00] 0xACDC0801 executes Draw Out Wire on Item 0xAA01 • [2019-02-18T12:30:10-02:00] 0xACDC0802 executes Straight Wire on Item 0xAA01 • [2019-02-18T12:30:20-02:00] 0xACDC0803 executes Cut Wire on Item 0xAA01 • [2019-02-18T12:30:30-02:00] 0xACDC0801 executes Draw Out Wire on Item 0xAA02 • [2019-02-18T12:30:40-02:00] 0xACDC0802 executes Straight Wire on Item 0xAA02 • [2019-02-18T12:30:50-02:00] 0xACDC0804 executes Point Wire on Item 0xAA01 • [2019-02-18T12:31:00-02:00] 0xACDC0801 executes Draw Out Wire on Item 0xAA03 • … Icons © freepik.com C. Di Ciccio, March 2021 Blockchain and smart contracts 38
- 39. Smart contracts can execute processes Bulk Buyer BB Trigger Smart Contract Manufact- urer Mf. Trigger API call: Order goods Blockchain Transaction (BCTX) Smart Contract effect Check conformance API call Middleman Mm. Trigger API call: Place order Execute internal logic BCTX Smart Contract effect Check conformance API call Weber et al.: Untrusted business process monitoring and execution using blockchain. In: Proc. of BPM. Springer, 2016. C. Di Ciccio, March 2021 Blockchain and smart contracts 39
- 40. Executing inter-organisational processes on the Blockchain: A model-driven approach D.C, Cecconi, Dumas et al. Blockchain support for collaborative business processes. Informatik Spektrum pp. 1–9 (May 2019) C. Di Ciccio, March 2021 Blockchain and smart contracts 40
- 41. Executing inter-organisational processes on the Blockchain: A model-driven approach Caterpillar Lorikeet 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-DrivenEngineering Tool for Blockchain-Based Business Process Executionand Asset.In: BPM Demos.CEUR.ws,2018. C. Di Ciccio, March 2021 Blockchain and smart contracts 41
- 42. Rationale C. Di Ciccio, March 2021 D.C. et al. Blockchain-Based Traceability of Inter-organisational Business Processes. In: BMSD. Springer, 2018. Blockchain and smart contracts 42
- 43. Rationale C. Di Ciccio, March 2021 D.C. et al. Blockchain-Based Traceability of Inter-organisational Business Processes. In: BMSD. Springer, 2018. Blockchain and smart contracts 43
- 44. Coming next: Smart contracts × supply chain (demo) Claudio Di Ciccio | http://diciccio.net | [email protected] Sapienza, University of Rome, Italy Blockchain Tech course 2020-21 at Sapienza: https://sites.google.com/uniroma1.it/cfa-msc-blockchaintech/
- 45. Blockchain and smart contracts: infrastructure and platforms Claudio Di Ciccio | http://diciccio.net | [email protected] Sapienza, University of Rome, Italy Blockchain Tech course 2020-21 at Sapienza: https://sites.google.com/uniroma1.it/cfa-msc-blockchaintech/
- 46. How about the real world? Oracles: From on-chain to off-chain and vice versa C. Di Ciccio, March 2021 Blockchain and smart contracts 46
- 48. Flight delay insurance: the FlightDelayPayout contract Payout in case of signalled problems with the flight Contact with the off-chain world Source: https://www.flickr.com/photos/michaelduxbury/5824469025 C. Di Ciccio, March 2021 Blockchain and smart contracts 48
- 50. The Oracle C. Di Ciccio, March 2021 Foundational Oracle Patterns: Connecting Blockchain to the Off-Chain World. BPM (Blockchain and RPA Forum) 2020: 35-51 DB Blockchain and smart contracts 50
- 51. The Oracle C. Di Ciccio, March 2021 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. Blockchain and smart contracts 51
- 52. Oracle patterns: Overview C. Di Ciccio, March 2021 Blockchain and smart contracts 52 Foundational Oracle Patterns: Connecting Blockchain to the Off-Chain World. BPM (Blockchain and RPA Forum) 2020: 35-51