RISQ - Colloque 2018 15h25 Jeremy Clark

1. Jeremy Clark
Blockchain
Technology:
Landscape
& Future
Directions

2. Jeremy Clark
• Assistant Professor at the Concordia Institute for Information Systems
Engineering (CIISE) in Montreal
• PhD from the University of Waterloo (2009)
• Team of eight graduate students
• Numerous academic papers on Bitcoin/Blockchain, including one of the
earliest
• Contributed to courses (Princeton, MIT) & textbook on Bitcoin/blockchain
• Testified to Senate and House committees on Bitcoin/blockchain
Where I Am

6. Digital Revolution
Blockchain

7. Digital Revolution
For business processes based on paper
records, digitization increases efficiency

8. 🚢

9. 🚢

10. 🚢

11. 🚢

12. 🚢

13. 🚢

14. Digital Revolution

15. Database
Digital Revolution

16. T-2351
T-4528
T-9636
T-9833

17. T-2351
T-4528
T-9636
T-9833
Who Owns the Database?
Privileged Position
Availability
Manage Access

18. T-2351
T-4528
T-9636
T-9833
Who Owns the Database?
Privileged Position
Availability
Manage Access
Reconciliation

19. T-2351
T-4528
T-9636
T-9833

20. T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833

21. T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
Disintermediation

22. T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
Blockchain

23. T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
Blockchain
Data cannot be changed once written
Data is only written if it is true (truth by definition)
Everyone sees the same data; no reconciliation
Data is readily available

24. T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
T-2351
T-4528
T-9636
T-9833
Blockchain
Data cannot be changed once written
Data is only written if it is true (truth by definition)
Everyone sees the same data; no reconciliation
Data is readily available
Data can activate processes which are validated

25. • Securities: stocks, bonds, derivatives, swaps,
repos and post-trade settlement
• Markets: land deeds, carbon credits
• Banking: inter-bank settlement, international
payments, remittances, micropayments, loyalty
• Provenance: luxury goods, organic certifications,
supply chain management
• Government: voting, registries
• Coordination: internet of things
• Identity management: KYC, PKI
• Fun: gambling, prediction markets
Use Cases

26. • Securities: stocks, bonds, derivatives, swaps,
repos and post-trade settlement
• Markets: land deeds, carbon credits
• Banking: inter-bank settlement, international
payments, remittances, micropayments, loyalty
• Provenance: luxury goods, organic certifications,
supply chain management
• Government: voting, registries
• Coordination: internet of things
• Identity management: KYC, PKI
• Fun: gambling, prediction markets
Use Cases
Blockchain systems can interact

27. Frequently Asked Questions
& common misconceptions

28. Relation to Bitcoin
Bitcoin is designed to be a currency (BTC)
Bitcoin is not a digital form of an existing currency
Thus not like Paypal, EFTs, interact-by-email
Bitcoin is decentralized: no central bank

29. The term blockchain
1) Bitcoin’s protocol for achieving a distributed
ledger maintained by an open network of profit-
seeking nodes
2) Any distributed ledger
3) The philosophy behind Bitcoin: digitizing
commodities, securities, deeds, contracts…

30. • Blockchains and (distributed) databases are similar
and somewhat interchangeable
• The emphasis is on different things
• Blockchains are for small data (1MB every 10 min)
• Blockchains are for validated data
• Blockchains are not about complex queries (you
download everything)
• Blockchains are secure against malicious nodes
Blockchain v. Database

31. • CAC-ISO-TC307: Blockchain and electronic
distributed ledger technologies
• Industry Consortiums: Various
Standards
Regulation
• Use-Case Specific: Mostly pertains to Bitcoin
• Taxation: capital gain
• Accounting (IFRS): intangible asset
• KYC/AML: Fintrac given authority
• ICOs/Trusts/Exchanges: Securities authorities

32. • By default, blockchains have no confidential
transactions
• Confidentiality can be added on with encryption but
non-trivial
• By default, blockchains have no identities
associated to transactions
• Identities can be added (or conversely, anonymity
strengthened)
Confidentiality & Privacy

33. Consistency?
Consensus through voting
Proof of Work

34. Consistency?
Consensus through voting
Honest majority

35. Consistency?
Consensus through voting
One vote per ________?
Honest majority

36. Consistency?
Consensus through voting
One vote per ________?
1) Entity:
trusted list of entities, closed network
Honest majority

37. Consistency?
Consensus through voting
One vote per ________?
1) Entity:
trusted list of entities, closed network
2) Unit of computational effort:
Bitcoin’s blockchain
No trust, open network
Honest majority

38. ACM Queue

39. 1980
1985
1990
1995
2000
2005
2010
2015
smart
contracts
public
keys as
identities
Byzantine
fault
tolerance
proof
of work
digital
cash
Merkle
Tree [33]
Haber &
Stornetta [22]
Haber &
Stornetta [23]
Benaloh &
de Mare [6]
Bayer, Haber,
Stornetta [5]
Ecash [10]
anti-spam[15]
hashcash [2]
Micro-
mint [44]
client
puzzles
[25]
offline
Ecash [32]
DigiCash
Byzantine
Generals [27]
Paxos [28]
PBFT [8]
Paxos made
simple [29]
computational
impostors [1]
Chaum
anonymous
communication
[9]
Chaum
security w/o
identification
[11]
b-money [13]
Bit gold [42]
private
blockchains
Bitcoin [34]
Ethereum
Szabo
essay [41]
Goldberg
disser-
tation [20]
Sybil attack
[14]
Nakamoto concensus
linked
timestamping,
verifiable logs

40. More resources

43.
Bitcoin and Cryptocurrency Technologies
Arvind Narayanan, Joseph Bonneau, Edward Felten,
Andrew Miller, Steven Goldfeder
with a preface by Jeremy Clark
Draft — Feb 9, 2016
Feedback welcome! Email ​bitcoinbook@lists.cs.princeton.edu
For the latest draft and supplementary materials including programming assignments,
see our ​Coursera course​.
The official version of this book will be published by Princeton University Press in 2016.
If you’d like to be notified when it’s available, please sign up ​here​.

44. ACM Queue

45. @PulpSpy
Q