Presentation together with Joris Bontje, CTO of Oneup.Company. The audience are mainly developers. Video recording: https://www.youtube.com/watch?v=43L08dn2y8s Event link: https://blockchainhackathon.eu/events/technology-deep-dive

1. Ethereum under the hood

2. Who are we?
• Joris Bontje
• @mids106
• http://OneUp.Company
• Pascal Van Hecke
• @vanheckeinfo
• http://Tokenengineers.com

3. Who are we?
• Joris Bontje
• @mids106
• http://OneUp.Company
• Pascal Van Hecke
• @vanheckeinfo
• http://Tokenengineers.com

4. Ethereum for Bitcoiners

5. Programming in Bitcoin
• Contains a deliberately simple scripting language
• A transaction = locking Bitcoin and describing how it can be unlocked
• Examples:
• Multisig: multiple signatures are needed to unlock
• CheckLocktimeVerify: Bitcoin only spendable at some point in future
• ….

7. Programming in Bitcoin
• Contains a relatively simple scripting language
• A transaction = locking Bitcoin and describing how it can be unlocked
• Examples:
• Multisig: multiple signatures are needed to unlock
• CheckLocktimeVerify: Bitcoin only spendable at some point in future
• ….
More ”opcodes”,
more functionality
Altcoin/Metacoin X

9. Ethereum: anything is programmable
“Classic “ blockchains
• Addresses
• Balance with “native” coin
• Transactions and blocks
Ethereum:
• Addresses
• …
• …
• Balance with Ether
• …
• Transactions and blocks
• …
• …

10. Ethereum: anything is programmable
“Classic “ blockchains
• Addresses
• Balance with “native” coin
• Transactions and blocks
Ethereum:
• Addresses
• + data storage
• + code
• Balance with Ether
• …
• Transactions and blocks
• …
• …

14. Ethereum: anything is programmable
“Classic “ blockchains
• Addresses
• Balance with “native” coin
• Transactions and blocks
Ethereum:
• Addresses
• + data storage
• + code
• Balance with Ether
• …
• Transactions and blocks
• …
• …

16. Ethereum: anything is programmable
“Classic “ blockchains
• Addresses
• Balance with “native” coin
• Transactions and blocks
Ethereum:
• Addresses
• + data storage
• + code
• Balance with Ether
• + application-specific tokens
with specific behaviour
• Transactions and blocks
• …
• …

17. Ethereum: anything is programmable
“Classic “ blockchains
• Addresses
• Balance with “native” coin
• Transactions and blocks
Ethereum:
• Addresses
• + data storage
• + code
• Balance with Ether
• + application-specific tokens
with specific behaviour
• Transactions and blocks
• + creation of contract code
• + calling contract code

20. Slow and primitive, but…
Promise:
A 15-year old can deploy business
logic that is:
• Verifiable
• Immutable
• Untamperable
• Untouchable

25. Smart contract pattern
1 Lock thing of value in contract
2 Contract code determines
redistribution
3 Based on information that is not
yet known

26. Smart contract pattern
1 Lock thing of value in contract
• Native crypto
• Tokens representing value… or
abilities
2 Contract code determines
redistribution
3 Based on information that is not
yet known

27. Smart contract pattern
1 Lock thing of value in contract
• Native crypto
• Tokens representing value… or
abilities
2 Contract code determines
redistribution
3 Based on information that is not yet
known
• Randomness
• Actor
• “Oracle”

28. Solidity

29. Solidity
Contract-oriented, high level language for the EVM
Statically typed, inheritance, libraries and syntax sugar
Contracts are like class instances
Public functions are the API
Contract state locally available on all nodes

30. Javascript like language

32. Compiles to EVM bytecode
TXVALUE PUSH 25 PUSH 10 PUSH 18 EXP
MUL LE NOT PUSH 34 JMPI STOP PUSH 34
JMP PUSH 0 TXDATA SLOAD NOT PUSH 0
TXDATA PUSH 1000 LT NOT MUL NOT NOT
PUSH 34 JMPI STOP PUSH 1 TXDATA PUSH 0
TXDATA SSTORE

37. https://ethereum.github.io/browser-solidity/

39. https://solidity.readthedocs.io

40. web3

42. web3 - Javascript API
// creation of contract object
var MyContract = web3.eth.contract(abi);
// initiate contract for an address
var myContractInstance =
MyContract.at('0x78e97bcc5b5dd9ed228fed7a4887c0d7287344a9');
var result = myContractInstance.myConstantMethod('myParam');
console.log(result) // '0x25434534534’
myContractInstance.myStateChangingMethod('someParam1', 23,
{value: 200, gas: 2000}, function(err, result){ ... });

44. Development Tools

49. Clients

56. Resources

58. What have people built so far?

62. Permissioned or public?