Blockchain is an open, distributed ledger that can record transactions between two parties efficiently and permanently. It works by linking transaction records into blocks secured by cryptography, forming a chain. Tampering with a block would change its hash and break the chain. Blockchains use consensus algorithms like proof-of-work and proof-of-stake to validate transactions without centralization. Smart contracts enable blockchain applications. Supply chain management may be a promising application area due to blockchain's decentralization, immutability, and transparency. Examples include partnerships between IBM/Walmart and Everledger for provenance tracking.

1. Demystifying Blockchain
for businesses
DR SCOTT TURNER
@SCOTTTURNERUON

2. From wikipedia
"an open, distributed ledger
that can record transactions
between two parties
efficiently and in a verifiable
and permanent way"

3. What is a Blockchain?

4. What is Blockchain?
Block 1 2 3
Hash EC 1A F1
Previous Hash 00 EC 1A
Genesis Block
Simple Hash values shown for simplicity – In Reality they are
a lot bigger
Encryption techniques used to produce the hash numbers

5. Could we tamper with the block?
Yes
But it would change the block’s hash
and therefore the previous block no
longer has the hash of the tampered
block and the chain broken.

6. Just recalculate the hashes
for the blocks before and
after the ‘tampered’ block
then?

7. Proof of Work and Consensus
 Proof of Work
The mechanism involves massive amount of
calculations to produce a valid hash – for
Bitcoin approx. 10 minutes
This would also has to be done for all the
following blocks in the chain as well
Still enough computing power still might be
able to do it.

8. Proof of Work and Consensus
 Consensus
 Not centralised
 When you join the network as a node – you get a
copy of the chain.
 Each one will check if it the blocks is valid by proof of
work
 Block is only accepted if over 50% of nodes agree on
it being valid
 To tamper you need to get control of over 50% of the
network.

9. Proof of Stake
Validators
Each has their own Coin locked up –
stake (like a bet)
If they have a block, they think can be
added, they put a stake on it
If the block gets added, they get back a
reward proportional to the stake.

10. Smart Contracts
Idea came before Cryptocurrency
Small program with a blockchain
Blockchain adds the validation
Ethereum is set-up around Smart
Contracts

11. Is Supply Chain the application area?
 Probably is one of them
The 3 properties of the blockchain technology:
 Decentralization
 Immutable
 Transparency

12. Is Supply Chain the application area?
 IBM and Walmart have teamed up
http://fortune.com/2017/08/22/walmart-blockchain-ibm-food-nestle-
unilever-tyson-dole/
 Leather, Blockchain and DNA
https://www.ledgerinsights.com/everledger-blockchain-
provenance-dna-tagging/
 Diamonds – De Beers https://www.ledgerinsights.com/debeers-
blockchain/

13. Considerations
 Transactions costs – adding to the chain costs, though views
are often free.
 Why do you want it decentralised?
 What happens if the ‘platform’ folds?
 The data is permanent – some issues with GDPR?
 Often not very environmental

14. Summary
 What is a blockchain?
 Some of the security features – proof of work,etc.
 Smart Contracts
 Based around Transactions.
 Supply chain might ne the killer application area
 Some examples
 Some issues to consider

15. Universities with Blockchain Research
Initiatives and Classes
 July 2018 University of
Northampton one of 28
https://diar.co/universities-
with-blockchain-research-
initiatives-and-classes/

16. Useful background
 https://www.youtube.com/watch?v=SSo_EIwHSd4 A
nice introduction to blockchain.
 Blockchain game, paper based game for teaching
some of the basics of blockchain -
https://www.youtube.com/watch?v=aHMgqNUsmvo