Blockchain is an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way. Each block contains a cryptographic hash of the previous block, transaction data, and a timestamp. New use cases for blockchain include distributed identity, where individuals would have control over their own data through decentralized identifiers rather than third parties acting as centralized identity providers as is common currently. Questions are welcome regarding distributed ledger technology and its applications.

1. BLOCKCHAIN
NEW USE-CASES
Abhilash K A
19 Sep 2021

2. Contents
• Blockchain – Use cases :
• New Use case - Blockchain in Identity
• Introduction to Blockchain
• Overview on Bitcoin
• DLT
• Blockchain – Classification

3. Blockchain Use cases
• IBM World wire
• Food Trust by IBM

4. IBM World Wire
Image Courtesy: IBM

5. Food Trust
Image Courtesy: snapperbuzz.com

6. New Use Case
• Distributed Identity

7. Internet
Image Courtesy: The New Yorker

8. Identity in Internet
• Initial days
• Mid 90s
• Platforms
• Decentralized Identity

9. Distributed Identity
Image courtesy: Hyperledger, Drummond Reed

10. Blockchain

11. Blockchain
• Blockchain is an
– open
– distributed ledger
– that can record
transactions
– between two parties
– efficiently and
– in a verifiable and
permanent way.
• source: hbr.org

12. Blockchain
• Blockchain is a growing list of records, called blocks,
that are linked using cryptography.
• Each block contains cryptographic hash of previous
block
• Each block contains transaction data and timestamp
• Source : Wikipedia.org

13. Distributed Systems

14. Distributed Systems
• There are many, notable
– Torrent (File Sharing system)
– Bitcoin

15. Bitcoin

16. Bitcoin
• Bitcoin is a decentralized digital currency,
without a central bank or single administrator,
that can be sent from user to user
on the peer-to-peer bitcoin network
without the need for intermediaries.
• Satoshi Nakamoto
• Initial Release : 9 Jan 2009
• Source: wikipedia.org

17. Blockchain

18. Why Blockchain…

19. Questions….
• Muhammad Saeed al-Sahhaf
Image courtesy: Google

20. Distributed
Ledger
Technology

21. Blocks – linked
Previous
Hash()
Current
Hash()
Transaction #20
Previous
Hash()
Current
Hash()
Transaction #21
Previous
Hash()
Current
Hash()
Transaction #22
Prev
Hash
Tran

22. Blocks – Merkle Root
Previous
Hash()
Current
Hash()
txn, txn, … ,txn
Previous
Hash()
Current
Hash()
txn, txn, … ,txn
Previous
Hash()
Current
Hash()
txn, txn, … ,txn
Prev
Hash
txn,
H(OUTPUT11, OUTPUT12)
Hash of the block
txn.. txn.. txn.. txn..
H(txn…)
OUTPUT01
H(txn…)
OUTPUT02
H(txn…)
OUTPUT03
H(txn…)
OUTPUT04
H(OUTPUT01, OUTPUT02)
OUTPUT11
H(OUTPUT01, OUTPUT02)
OUTPUT12

23. Consensus • PoW
– (Proof of Work)
• PoS
– (Proof of Stake)
• PBFT
– (Practical Byzantine
Fault Tolerance)
• to achieve overall
system reliability in the
presence of a number of
faulty processes.
• applications of
consensus include
agreeing on what
transactions to commit
to a database
• Ref: wikipedia.org

24. • Peer 2 Peer Network
1
• Cryptography
Asymmetric
2
• Distributed Consensus
3
Distributed Ledger Technology .. Summarized.

25. Salient Features

26. Blockchain Classification
• Public
• Private
• Permissioned
• Non-Permissioned

27. Classification - Matrix

28. Private Blockchain
PRIVATE BLOCKCHAIN
NIZATION TYPE Single entity or organization
USERS Known & trusted participants
ACCESS Access fully restricted
WORK TYPE Centralized; single point of failure
PERATION Pre-approved participants can read &/or initiate transactions
RIFICATION Single validator node or central authority to create a block
MUTABILITY Secured by distributed consensus
ONSENSUS
ECHANISM
Voting or variations of PoW/PoS consensus algorithms
ECURITY Security is dependent on the blockchain architecture adopted.
TRUST Entrusted; central control
ACTION SPEED High; secs to create a block
ENERGY
NSUMPTION
Low
ALABILITY Better scalability as high storage and computational power is not requir

29. Usage…
Do you
need
to
store
the
State?
Are
there
multipl
e
writers
?
Can
you
use an
always
Online
TTP?
Are all
writers
known
?
Are all
writers
truste
d?
Is public
verifiabili
ty
required
?
Permissionles
s
Blockchain
Public
Permissioned
Blockchain
Private
Permissioned
Blockchain
Don’t use
Blockchain
YES
NO NO YES
YES
NO
NO YES
YES YES NO NO

30. HyperLedger

31. Hyperledger Fabric - Nodes

32. Hyperledger

33. New Use Case
• Distributed Identity

34. Internet
Image Courtesy: The New Yorker

35. Identity in Internet
• Initial days
• Mid 90s
• Platforms
• Decentralized Identity
No control of over their own data.

36. Centralized Identity
Image courtesy: Hyperledger, Drummond Reed

37. Third party as Identity Provider
Image courtesy: Hyperledger, Drummond Reed

38. Distributed Identity
Image courtesy: Hyperledger, Drummond Reed

39. SSI in Action
• DID would be based on
standard
• DID would be using
pairwise unique
pseudonym.
• Zero knowledge proofs
• Verifiable credentials
Image courtesy: Sovrin Foundation

40. QUESTIONS?

41. APPENDIX

42. Cryptography
In ancient India
https://en.wikipedia.org/wiki/Mulabhadra
https://en.wikipedia.org/wiki/Mlecchita_vikalpa
Modern Cryptography
https://en.wikipedia.org/wiki/Cryptography
https://en.wikipedia.org/wiki/Advanced_Encryption_Standard
https://en.wikipedia.org/wiki/Data_Encryption_Standard
https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange
https://en.wikipedia.org/wiki/Zero-knowledge_proof

43. Blockchain
Technology