James Smith @floppy @ODILabs

Blockchains for global data infrastructure

“...in a relatively short time the word blockchain has become detached from its technological roots … to become one of those almost generic chromewash terms, like “big data” or “cloud” to deliver a superficial veneer of futurism.”

David Birch, Consult Hyperion, in Finextra

● Explain the differences between centralised, decentralised and distributed systems

● List the 5 core features of blockchain technology

● Understand blockchain security and privacy implications

● Assess critically when a blockchain is needed (or not!)

Learning Outcomes

What is data infrastructure?

It’s a database! But:

● widely distributed● allows many writers● don’t have to trust anyone● networked consensus● immutable

What is a Blockchain?

Distributed systems

From “On Distributed Communications” by Paul Baran, 1964 - http://www.rand.org/pubs/research_memoranda/RM3420.html

● widely distributed● allows many writers● don’t have to trust anyone● networked consensus● immutable

Private database

Shared database

● widely distributed● allows many writers● don’t have to trust anyone● networked consensus● immutable

Mutable

Immutable

● widely distributed● allows many writers● don’t have to trust anyone● networked consensus● immutable

No central authority

● widely distributed● allows many writers● don’t have to trust anyone● networked consensus● immutable

Decentralisation

● widely distributed● allows many writers● don’t have to trust anyone● networked consensus● immutable

Distributed

Consensus

● widely distributed● allows many writers● don’t have to trust anyone● networked consensus● immutable

Mining

“A” blockchain, or “THE” blockchain?

Scalability

● How many blockchains?○ security of network○ size of database

● Splitting & merging blockchains● Archiving

Is immutability always a good thing?

Immutable?

Discuss: why would you want to change history in a database?

● “Official Truth”● Right to be forgotten● Changing gender● Domestic abuse● Illegal information

Immutability

● Public blockchains● Private or “permissioned”

blockchains○ Within an organisation

● Different levels of access○ Hybrid systems

Access

● WWW● IPFS● Ethereum● MaidSafe

… and a whole load of more traditional database technologies

Distributed technologies

● Data in a public blockchain is inherently publicly shared

● Personal data can lie anywhere on the data spectrum○ conscious choice of position

● Transaction data

Privacy

Protecting Privacy

● Trusted network○ But then, why a blockchain?

● Hybrid systems● Encryption

○ Compromised keys○ Lost keys○ Broken algorithms

“it is once again important to note that blockchains do NOT solve privacy issues, and are an authenticity solution only”

“Privacy on the Blockchain” by Vitalik Buterinblog.ethereum.org/2016/01/15/privacy-on-the-blockchain

Do you need a blockchain?

https://medium.com/@sbmeunier/when-do-you-need-blockchain-decision-models-a5c40e7c9ba1

● widely distributed● allows many writers● don’t have to trust anyone● networked consensus● immutable

bit.ly/1onu7Cp

● Bitcoin● Everledger● Provenance

● DNS?● Document revocation?● International shipping?

Use cases

Standards

● Standards for a network of data● Ownership & licensing● Linking to the rest of the web

○ What’s the URL for a transaction?

○ Redirection

Linking

● Explain the differences between centralised, decentralised and distributed systems

● List the 5 core features of blockchain technology

● Understand blockchain security and privacy implications

● Assess critically when a blockchain is needed (or not!)

Learning Outcomes

Download fromhttp://theodi.org/publications