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Blockchains:
a New Platform for
Semantically Enabled
Transactions
Prof. John Domingue
Director, Knowledge Media Institute,...
Caveat
• Semantic Web
• Semantic Web Services
• Blockchains
MOTIVATION
Our Position in the SW World
WEB IS A PLATFORM
E-commerce
Search	Engine Social
Web	Portal Travel Online	Services
Cloud	computing
$28.83
$15.84
$12.29
$...
Blockchain <-> SWS Relationship (1/2)
• Blockchains
implement trust
• New (transaction)
platform
Blockchain <-> SWS Relationship (2/2)
• Simple concept with complex
implementation
• Re-use important
• Identification imp...
BLOCKCHAINS IMPACT
Blockchain
10
World	Economic	Forum	Survey	Projects	
Blockchain	‘Tipping	Point’	by	2023
Santander:	Blockchain Tech	Can	Save...
IBM: Device Democracy
http://www-935.ibm.com/services/multimedia/GBE03620USEN.pdf
Distributed Autonomous Organisations
BLOCKCHAIN ELEMENTS
What is a blockchain?
A	blockchain is	a	
permissionless
distributed	database,	
based	on	the	bitcoin	
protocol	that	
mainta...
Cryptographic Hash Function
https://en.wikipedia.org/wiki/Cryptographic_hash_function
Blockchain is a Linked List (1/2)
A	blockchain	can	be	thought	of	as	a	linked	list	of	transactions	
that	is	built	with	hash...
Blockchain is a Linked List (2/2)
A	blockchain actually	contains	
two	different	hash	structures.	
The	first	is	a	hash	chai...
Ethereum Blockchain Platform
Ethereum is	a	cryptocurrency	platform	and	Turing-complete	programming	
framework	intended	to	allow	a	network	of	peers	to	a...
Ethereum Blockchain Platform
Ethereum is	a	100%	open	source	software	platform	to	build	distributed,	
decentralized	applica...
Ethereum Virtual Machine
Sources:	Ethereum Development	Tutorial
The	Ethereum Virtual	Machine	can	be	thought	of	as	a	large	...
What are Ethereum Contracts?
‘Smart’	contracts	are	computer	protocols	that	facilitate,	verify,	or	enforce	the	
negotiation...
Contracts in Ethereum
Maintain	a	data	store	
representing	
something	which	is	
useful	to	either	other	
contracts	or	to	the...
DApps
Source:	Ethereum - Stephan	Tual
A	Đapp is	a	decentralised application	which	serves	some	
specific	purpose	 to	its	us...
DBrowsers
It	is	an	end	user	interface	onto	
the	Ethereum blockchain.
A	DBrowser is	how	users	will	find	
and	interact	with	...
Characteristics of Blockchain DApps
• Shared database
• Multiple writers
• Absence of trust
• Disintermediation
• Transact...
HIGHER EDUCATIONAL
EXAMPLE
Demos	of	movies	available	at:	http://blockchain.open.ac.uk/
Course	Contract
Functions:
Storage:
enrol
unenrol
getStudents
studentsPaid[address=0.6,	address=0….	]
students	[address,	a...
Jane	enrols	on	an	OpenLearn Course
Higher Education Disaggregation
BLOCKCHAINS, SERVICES
AND SEMANTICS
Services -> Smart Contracts
Web	service
Operation	1
Operation	2
Operation	N
input
input
input
output
output
output
.
..
Services -> Smart Contracts
Web	service
Operation	1
Operation	2
Operation	N
input
input
input
output
output
output
.
..
Services -> Smart Contracts
Web	service
Operation	1
Operation	2
Operation	N
.
..
Services -> Smart Contracts
Web	service
Operation	1
Operation	2
Operation	N
.
..
Services -> Smart Contracts
Web	service
Operation	1
Operation	2
Operation	N
.
..
Services -> Smart Contracts
Smart	Contract
.
..
Transaction	1
Transaction	2
Transaction	N
Services -> Smart Contracts
Distributed	Autonomous
Organisation
.
..
Transaction	1
Transaction	2
Transaction	N
• From
• To
• Value
• Gas
• Gas Price
• Data
• Nonce
web3.eth.sendTransaction(transactionObject[,	callback])
Transaction C...
• Block Hash
• Block Number
• Transaction Hash
• Transaction Index
• From
• To
• Cumulative Gas Used
• Gas Used
• Contract...
Minimal Service Model
http://iserve.kmi.open.ac.uk/
http://linked-usdl.org/
http://linked-usdl.org/
BLONDiE Ontology
Matthew	English https://github.com/EIS-Bonn/BLONDiE/
Transaction
• From
• To
• Input
– Value
– Data
• Cost
– Currency
– Price
• Block information
• Contract
• Condition
– Fina...
Smart Contract
• Transactions
• Condition
– Financial condition
– Non financial condition
• Effect
– Financial effect
– No...
SUMMARY
Related events
New	York,	USA,	July	6-9	2016
Summary (1/2)
• Blockchain attracting a lot of commercial
and community interest
– Trusted mediator for legal and financia...
Summary (2/2)
• Small subset of the SW/LoD community
focused on processes/services/APIs
• Lot to offer
– Identification
– ...
Acknowledgements
• KMi@OU Implementation Team
– Michelle Bachler
– Kevin Quick
• Discussants
– Sören Auer, Fraunhofer
– Ad...
blockchain.open.ac.uk
Blockchains  a new platform for semantically enabled transactions public
Blockchains  a new platform for semantically enabled transactions public
Blockchains  a new platform for semantically enabled transactions public
Blockchains  a new platform for semantically enabled transactions public
Blockchains  a new platform for semantically enabled transactions public
Blockchains  a new platform for semantically enabled transactions public
Blockchains  a new platform for semantically enabled transactions public
Blockchains  a new platform for semantically enabled transactions public
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Blockchains a new platform for semantically enabled transactions public

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Keynote at the SALAD Workshop at ESWC 2016. Gives an overview of blockchains and some thoughts on the link to the Semantic Web, Linked Data and Semantic Web Services

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Blockchains a new platform for semantically enabled transactions public

  1. 1. Blockchains: a New Platform for Semantically Enabled Transactions Prof. John Domingue Director, Knowledge Media Institute, the Open University, UK President STI International http://kmi.open.ac.uk/
  2. 2. Caveat • Semantic Web • Semantic Web Services • Blockchains
  3. 3. MOTIVATION
  4. 4. Our Position in the SW World
  5. 5. WEB IS A PLATFORM E-commerce Search Engine Social Web Portal Travel Online Services Cloud computing $28.83 $15.84 $12.29 $10.56 $17.93 $74.98 $107 $9.22 $6.77 $8.59 $6.3 $6.67 $5.37 $4.97 $3.63 $2.99 $3.1 $1.5 $1.40 $0.9 $2.22
  6. 6. Blockchain <-> SWS Relationship (1/2) • Blockchains implement trust • New (transaction) platform
  7. 7. Blockchain <-> SWS Relationship (2/2) • Simple concept with complex implementation • Re-use important • Identification important • No inbuilt search • Interoperates with plethora of systems • Implements legal, financial and asset based transactions
  8. 8. BLOCKCHAINS IMPACT
  9. 9. Blockchain 10 World Economic Forum Survey Projects Blockchain ‘Tipping Point’ by 2023 Santander: Blockchain Tech Can Save Banks $20 Billion a Year
  10. 10. IBM: Device Democracy http://www-935.ibm.com/services/multimedia/GBE03620USEN.pdf
  11. 11. Distributed Autonomous Organisations
  12. 12. BLOCKCHAIN ELEMENTS
  13. 13. What is a blockchain? A blockchain is a permissionless distributed database, based on the bitcoin protocol that maintains a continuously growing list of transactional data records hardened against tampering and revision, even by operators of the data store's nodes. The initial and most widely known application of the blockchain technology is the public ledger of transactions for bitcoin and the inspiration of similar distributed ledgers known as altchains. Each blockchain record is enforced cryptographically and hosted on machines working as a data store Source: Wikipedia
  14. 14. Cryptographic Hash Function https://en.wikipedia.org/wiki/Cryptographic_hash_function
  15. 15. Blockchain is a Linked List (1/2) A blockchain can be thought of as a linked list of transactions that is built with hash pointers instead of pointers Source: Bitcoin and Cryptocurrency Technologies - Arvind Narayanan, Joseph Bonneau, Edward Felten, Andrew Miller, Steven Goldfeder
  16. 16. Blockchain is a Linked List (2/2) A blockchain actually contains two different hash structures. The first is a hash chain of blocks that links the different blocks to one another. The second is internal to each block and is a Merkle Tree of transactions within the blocks. This allows for efficiently verifiable proofs that a transaction was included in a block.
  17. 17. Ethereum Blockchain Platform
  18. 18. Ethereum is a cryptocurrency platform and Turing-complete programming framework intended to allow a network of peers to administer their own stateful user-created smart contracts in the absence of central authority. It features a blockchain-based virtual machine that securely records and incentivizes the validation of transactions, i.e. code executions, made through a cryptocurrency called ether. Ethereum takes the primary developments used by BitTorrent and Bitcoin, the peer to peer network and the blockchain, and generalizes them in order to allow developers to use these technologies for any purpose. Source: Wikipedia Ethereum Blockchain Platform
  19. 19. Ethereum Blockchain Platform Ethereum is a 100% open source software platform to build distributed, decentralized applications Ethereum is 100% peer to peer, censorship-proof and corruption-proof. Ethereum can be used to build anything: Asset issuance, crowdfunding, domain registration, title registration,predictionmarkets, internet of things, voting, educational certificate issuing systems, hundreds of applications Source: Ethereum slides - Stephan Tual and Ethereum in 40 minites by Vitalik Buterin
  20. 20. Ethereum Virtual Machine Sources: Ethereum Development Tutorial The Ethereum Virtual Machine can be thought of as a large decentralized computer containing millions of objects, called "accounts", which have the ability to maintain an internal database, execute code and talk to each other. There are 2 types of Accounts: Externally owned account (EOA): an account controlled by a private key that has the ability to send ether and messages from it. ‘Smart’ Contract: an account that has its own code, and is controlled by code. Any user can trigger an action by sending a transaction from an EOA, setting Ethereum's wheels in motion. If the destination of the transaction is another EOA, then the transaction may transfer some ether but otherwise does nothing However, if the destination is a ‘Smart’ Contract, then the contract in turn activates, and automatically runs its code.
  21. 21. What are Ethereum Contracts? ‘Smart’ contracts are computer protocols that facilitate, verify, or enforce the negotiation or performance of a contract. ‘Smart’ contracts can be partially or fully self-executing, self-enforcing, or both. Smart contracts in Ethereum have the ability to read/write to their own internal storage, read the storage of the received message, and send messages to other contracts, triggering their execution in turn Sources: Wikipedia and Ethereum Development Tutorial and Ethereum - Introduction to Smart Contracts
  22. 22. Contracts in Ethereum Maintain a data store representing something which is useful to either other contracts or to the outside world Serve as a sort of externally owned account with a more complicated access policy Manage an ongoing contract or relationship between multiple users Provide functions to other contracts; essentially serving as a software library. Contracts in Ethereum generally serve 4 purposes: source: Richard Gendal Brown “A Simple Model for Smart Contracts” http://gendal.me/2015/02/10/a-simple-model-for-smart-contracts/
  23. 23. DApps Source: Ethereum - Stephan Tual A Đapp is a decentralised application which serves some specific purpose to its users, but which has the important property that the application itself does not depend on any specific party existing. Rather than serving as a front-end for selling or providing a specific party's services, a Đapp is a tool for people and organizations on different sides of an interaction use to come together without any centralized intermediary. A Dapp consists of two parts: a frontend, written in HTML or QML, and a backend (think of it as the ‘database’ for your frontend).
  24. 24. DBrowsers It is an end user interface onto the Ethereum blockchain. A DBrowser is how users will find and interact with DApps ‘Mist’ is the name of the Ethereum DBrowser.
  25. 25. Characteristics of Blockchain DApps • Shared database • Multiple writers • Absence of trust • Disintermediation • Transaction interaction • Set rules • Validators • Asset backing http://www.multichain.com/blog/2015/11/avoiding-pointless-blockchain-project/
  26. 26. HIGHER EDUCATIONAL EXAMPLE
  27. 27. Demos of movies available at: http://blockchain.open.ac.uk/
  28. 28. Course Contract Functions: Storage: enrol unenrol getStudents studentsPaid[address=0.6, address=0…. ] students [address, address, address] Course Administration ViewStudent View Enrol for 6 ETH! your Ethereum address password to private key Signing this transaction will transfer 6 ETH + gas from your account. Estimated gas cost is 0.02 ETH. Maximum gas cost is set to 0.05 ETH Enrol Student Enrolment Page Signed TX Unenrol Student Admin Ethereum address Admin password to private key Signing this transaction will transfer 6 ETH + gas from course admin account. Estimated gas cost is 0.02 ETH. Maximum gas cost is set to 0.05 ETH Unenrol Course Admin Page Signed TX Student List (Listing students is a free transaction) Course Enrolment Page Signed TX Student Address Array unenrolStudent Account 11 Student Account 23 Student Account 45 Student Account 67 Student Account 89 unenrol unenrol unenrol unenrol Student Account 67 Course Smart Contract
  29. 29. Jane enrols on an OpenLearn Course
  30. 30. Higher Education Disaggregation
  31. 31. BLOCKCHAINS, SERVICES AND SEMANTICS
  32. 32. Services -> Smart Contracts Web service Operation 1 Operation 2 Operation N input input input output output output . ..
  33. 33. Services -> Smart Contracts Web service Operation 1 Operation 2 Operation N input input input output output output . ..
  34. 34. Services -> Smart Contracts Web service Operation 1 Operation 2 Operation N . ..
  35. 35. Services -> Smart Contracts Web service Operation 1 Operation 2 Operation N . ..
  36. 36. Services -> Smart Contracts Web service Operation 1 Operation 2 Operation N . ..
  37. 37. Services -> Smart Contracts Smart Contract . .. Transaction 1 Transaction 2 Transaction N
  38. 38. Services -> Smart Contracts Distributed Autonomous Organisation . .. Transaction 1 Transaction 2 Transaction N
  39. 39. • From • To • Value • Gas • Gas Price • Data • Nonce web3.eth.sendTransaction(transactionObject[, callback]) Transaction Creation Object
  40. 40. • Block Hash • Block Number • Transaction Hash • Transaction Index • From • To • Cumulative Gas Used • Gas Used • Contract Address • Logs Transaction Receipt Object web3.eth.getTransactionReceipt(hashString [, callback])
  41. 41. Minimal Service Model http://iserve.kmi.open.ac.uk/
  42. 42. http://linked-usdl.org/
  43. 43. http://linked-usdl.org/
  44. 44. BLONDiE Ontology Matthew English https://github.com/EIS-Bonn/BLONDiE/
  45. 45. Transaction • From • To • Input – Value – Data • Cost – Currency – Price • Block information • Contract • Condition – Financial condition – Non financial condition • Effect – Financial effect – Non financial effect • History
  46. 46. Smart Contract • Transactions • Condition – Financial condition – Non financial condition • Effect – Financial effect – Non financial effect
  47. 47. SUMMARY
  48. 48. Related events New York, USA, July 6-9 2016
  49. 49. Summary (1/2) • Blockchain attracting a lot of commercial and community interest – Trusted mediator for legal and financial transactions – IoT platform – Disaggregation and disintermediation – Leaderless Distributed Autonomous Organisations
  50. 50. Summary (2/2) • Small subset of the SW/LoD community focused on processes/services/APIs • Lot to offer – Identification – Search – Re-use – Interoperability – Automation • Machine <-> machine communication in a human populated world
  51. 51. Acknowledgements • KMi@OU Implementation Team – Michelle Bachler – Kevin Quick • Discussants – Sören Auer, Fraunhofer – Adi Ben-Ari, Applied Blockchain – Carla Casilli, Mozilla Open Badges – Marc Eisenstadt, OU – Matthew English, Fraunhofer – Denis Gillet, EPFL – Hugh Halford-Thompson, Blockchain Tech Ltd – William Knottenbelt, Imperial College – Konstantin Kudryavtsev, Ethcore – Gary McKay, APII – Rebecca Migirov, Consensys – Titi Roman, Sintef – Philipp Schmidt, MIT Media Lab – Mike Sharples, OU – Elena Simperl, University of Southampton – Ashley Taylor, Consensys – Sergej Zerr, University of Southampton • Graphics – Harriett Cornish, OU
  52. 52. blockchain.open.ac.uk

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