This is my gentle intro to blockchain talk given at FC Bayern Hackdays - From the disruption of trust to how to deploy a HelloWorld SmartContract on a local instance of Ethereum using Truffle and Ganache.

1. A Gentle Introduction To
Blockchain With Ethereum
Johann Romefort, Tech Evangelist at Stylight
Twitter: @romefort
Blog: http://romefort.net
LinkedIn: http://linkedin.com/in/romefort
Email: johann.romefort@stylight.com

2. Agenda
● The Trust Industry
● Disruptive Nature of Blockchain
● Ethereum
● Demo!

3. What Is the Buzz about
Blockchain

5. The History of
Trust and
Exchange of
Value

6. 3500 Years Ago: The Signet Ring
Signet rings have been used since as far back as 3500 BC when the people of
Mesopotamia began using them as a method of authenticity. Each was unique to one
person.

7. Today: 3rd-Party
Trust Guarantors
● Banks
● Insurance
● Land registries
● Governments
● Credit companies
● Legal Agencies

8. Trust Comes at
a Price
● Operational Costs
● Risk
● Time
● Centralization

9. 3rd-Party Trust Is
Fragile and Disrupted
● 2008 financial meltdown
● Government surveillance
● Elections
● Social media giants
● Data breaches

10. The Edelman Trust Barometer
Source: https://www.scribd.com/document/336621519/2017-Edelman-Trust-Barometer-Executive-Summary

11. The
Double-Spending
Problem
● You need to make sure the
ownership of the item of
value is moving from A to B
● In a digital world this is a
problem as assets can be
copied.
● This is why we needed 3rd
party which we can trust
and can ensure the validity
of the transaction

12. Until January 3rd,
2009
First blockchain implementation
deployed under the name:
“Bitcoin: A Peer-to-Peer
Electronic Cash System”
By Satoshi Nakamoto

13. The Distributed and
Transparent Nature of
Blockchain

14. What is
Blockchain?
● It’s an immutable distributed public ledger
● All transactions are timestamped and recorded
into blocks
● Distributed database with no single point of
failure
● Can’t be controlled by authorities such as
government due to its decentralized nature
● Solve the double-spending problem without
need for 3rd party of trust.

15. What is a Hash?
● Mathematical function which turns data into a
fingerprint of that data called
● You can’t deduce the data from the hash.
● The same data will have the same Hash.
● Slightly different data will have a totally different hash

16. What about Ethereum?
● It’s the second largest Blockchain implementation
● It can be a seen as a blockchain of second generation
● It contains new features such as Smart Contracts

17. What’s a Block?
● Bundle transactions
● Contains previous block hash
● All blocks are linked through their hashes
● You can’t change the data in one block
without breaking the chain
● Unless you mine it all over again

18. What’s a transaction?
● An operation that writes data on the blockchain
● Each transaction incurs a fee
● Simple transaction sending ETH from one address to
another
● More complicated transactions involve Smart Contracts

19. Smart Contracts
● Introduced in Ethereum Blockchain
● Run code directly on the blockchain
● Each smart contract has its own wallet
● Smart Contracts can invoke each others
● Written in Solidity

20. Enabling New
kinds of
Organizations
● DAO: Decentralized
Autonomous
Organization
● New type of
organization governed
by multiple smart
contracts
● Token holders can be
granted the right to
vote for example

21. Developing with Ethereum

22. Many chains available
● Main Net: This is the production network - Don’t use it
for development purposes!
● Rinkeby: https://www.rinkeby.io/#stats
○ PoA (Proof of Authority)
○ Immune to Spam attacks
○ Supported by geth only
○ Request ether through faucet: https://faucet.rinkeby.io/
● Ropsten: Best reproduce the current prod. Env.
○ Subject to Spam
○ Ether can be mined or requested
● Solo Network

24. Truffle - development framework for Ethereum

25. Setting up our development
environment
npm install -g truffle
npm install -g ganache-cli
truffle init
ganache-cli -p 7545

26. Ganache run a
local EVM
(Ethereum Virtual
Machine)
Also:
● Create accounts
● their private keys
● Fund the accounts
with 100ETH

27. Our first Smart Contract:
HelloWorld.sol

28. Write the migration
Save this in migrations/2_deploy

29. Adjust truffle.js
You can also get rid of the truffle-config.js file // depending on your platform

30. Let’s compile and
deploy our contract
truffle compile
truffle migrate --network development
Compile will compile our Solidity code to bytecode (the code that the Ethereum Virtual
Machine (EVM) understands), in our case, Ganache emulates the EVM.
Migrate will deploy the code to the blockchain, in our case, the blockchain could be found in
the network “development” we set earlier in the “truffle-config.js” file.

31. Migration in progress...

32. Using Truffle console

33. Interact with the Contract
1/get an instance
2/get the contract
address
3/get the message var content

34. If you prefer a GUI

35. Questions?