After enormous cryptocurrencies value gains this year, Blockchain - their underneath algorithm is a topic that gets both a lot of exposure and confusion among developers. In this presentation, I’m going to create a glossary that will guide you in further exploration and sort out your knowledge. We will discuss not only what Blockchain is but also why it is (or isn’t) the big thing. Everything using easy to grasp JavaScript code examples. Prepare yourself for surfing on dangerous hype-wave - it’s easy to drown. Repository of Presentation: https://github.com/ArturSkowronski/naivechain Presented: 4Developers Łódź (https://lodz.4developers.org.pl), Kraków, 09.11.2017 KrakowJS (http://conf.krakowjs.pl/), Krakow, 29.09.2017

1. DEVELOPER’S PERSPECTIVE
BLOCKCHAIN

2. TEXT
HOW TO BECOME RICH
INVESTOR’S PERSPECTIVE

3. BITCOINAIRE
BLOCKCHAIN, ANYBODY ?

4. BITCOINAIRE

5. MtGox Fraud
Initial Whitepaper
Initial Whitepaper
WTF?

7. TEXT
George Soros
LIBERTARIANS
KILL THE BANKS AND BANKERS

8. TEXT
INVESTORS
UNCORRELATED ASSET

9. DEVELOPERS
BLOCKCHAIN TECHNOLOGY

10. TEXT

11. TEXT

14. DOUBLE SPENDING

15. TEXT

16. ?

17. TEXT
LEDGER

18. CENTRALISED

19. TEXT
TRUST

20. TEXT
DISTRIBUTED LEDGER ?

21. POLITICALLY DECENTRALISED
ARCHITECTURALLY DECENTRALISED LOGICALLY DECENTRALISED

22. TEXT
CONSENSUS TECHNIQUE…

23. TEXT
…USING MATH

24. TEXT
LET’S CODEBASED ON NAIVECHAIN BY @LHARTIKK
@ARTURSKOWRONSKI/NAIVECHAIN

25. TEXT
P2P (WebSockets)
Interface (HTTP)
P2P (WebSockets)
Interface (HTTP)
P2P (WebSockets)
Interface (HTTP)

26. class Block {
constructor(index, previousHash, data, hash) {
this.index = index;
this.previousHash = previousHash;
this.hash = hash;
this.data = data;
}
}
BLOCK PART

27. class Block {
constructor(index, previousHash, data, hash) {
this.index = index;
this.previousHash = previousHash;
this.hash = hash;
this.data = data;
}
}
BLOCK PART

28. class Block {
constructor(index, previousHash, data, hash) {
this.index = index;
this.previousHash = previousHash;
this.hash = hash;
this.data = data;
}
}
BLOCK PART

29. class Block {
constructor(index, previousHash, data, hash) {
this.index = index;
this.previousHash = previousHash;
this.hash = hash;
this.data = data;
}
}
BLOCK PART

30. class Block {
constructor(index, previousHash, data, hash) {
this.index = index;
this.previousHash = previousHash;
this.hash = hash;
this.data = data;
}
}
BLOCK PART

31. class Chain {
constructor() {
this.blockchain = [GenesisBlock()];
}
chain() {
return this.blockchain
}
latestBlock () {return last(this.blockchain)};
};
CHAIN PART

32. class Chain {
constructor() {
this.blockchain = [GenesisBlock()];
}
chain() {
return this.blockchain
}
latestBlock () {return last(this.blockchain)};
};
CHAIN PART

33. class Chain {
constructor() {
this.blockchain = [GenesisBlock()];
}
chain() {
return this.blockchain
}
latestBlock () {return last(this.blockchain)};
};
CHAIN PART

34. GENESIS BLOCK
const GenesisBlock = () => {
return new Block(
index: 0,
previousHash: ”0",
data: "my genesis block!!",
hash: ”816534932c2b7154836da6afc”
);
};

35. MINING BLOCK
let chain = new Chain();
const mineBlock = (data) => {
const newBlock = NextBlock(chain.latestBlock(), data);
return chain.add(newBlock);
};

36. MINING BLOCK
let chain = new Chain();
const mineBlock = (data) => {
const newBlock = NextBlock(chain.latestBlock(), data);
return chain.add(newBlock);
};

37. MINING BLOCK
const NextBlock = (prevBlock, blockData) => {
const index = prevBlock.index + 1;
const prevHash = prevBlock.hash
const hash = calculateHash(index, prevHash, blockData);
return new Block(index, prevHash, ts, blockData, hash);
};

38. MINING BLOCK
const NextBlock = (prevBlock, blockData) => {
const index = prevBlock.index + 1;
const prevHash = prevBlock.hash
const hash = calculateHash(index, prevHash, blockData);
return new Block(index, prevHash, ts, blockData, hash);
};

39. MINING BLOCK
const NextBlock = (prevBlock, blockData) => {
const index = prevBlock.index + 1;
const prevHash = prevBlock.hash
const hash = calculateHash(index, prevHash, blockData);
return new Block(index, prevHash, ts, blockData, hash);
};

40. MINING BLOCK
const NextBlock = (prevBlock, blockData) => {
const index = prevBlock.index + 1;
const prevHash = prevBlock.hash
const hash = calculateHash(index, prevHash, blockData);
return new Block(index, prevHash, ts, blockData, hash);
};

41. CALCULATE HASH
const calculateHash = (index, prevHash, data) => {
return CryptoJS.SHA256(`${index} ${prevHash} ${data}`)
};

42. MINING BLOCK
const NextBlock = (prevBlock, blockData) => {
const index = prevBlock.index + 1;
const prevHash = prevBlock.hash
const hash = calculateHash(index, prevHash, blockData);
return new Block(index, prevHash, blockData, hash);
};

43. MINING BLOCK
let chain = new Chain();
const mineBlock = (data) => {
const newBlock = NextBlock(chain.latestBlock(), data);
return chain.add(newBlock);
};

44. ADDING BLOCK TO CHAIN
class Chain {
(…)
add(newBlock) {
if (isValidNewBlock(newBlock, this.latestBlock())) {
this.blockchain.push(newBlock)
}
return {
'type': RESPONSE_BLOCKCHAIN,
‘data':[latestBlock()]}
}
}
latestBlock () {return last(this.blockchain)};
};

45. ADDING BLOCK TO CHAIN
class Chain {
(…)
add(newBlock) {
if (isValidNewBlock(newBlock, this.latestBlock())) {
this.blockchain.push(newBlock)
}
return {
'type': RESPONSE_BLOCKCHAIN,
‘data':[latestBlock()]}
}
}
latestBlock () {return last(this.blockchain)};
};

46. BLOCK VALIDATION
const isValidNewBlock = (newBlock, previousBlock) => {
if (previousBlock.index + 1 !== newBlock.index) {
return false;
}
if (previousBlock.hash !== newBlock.previousHash) {
return false;
}
if (calculateHashForBlock(newBlock) !== newBlock.hash) {
return false;
}
return true;
};

47. BLOCK VALIDATION
const isValidNewBlock = (newBlock, previousBlock) => {
if (previousBlock.index + 1 !== newBlock.index) {
return false;
}
if (previousBlock.hash !== newBlock.previousHash) {
return false;
}
if (calculateHashForBlock(newBlock) !== newBlock.hash) {
return false;
}
return true;
};

48. BLOCK VALIDATION
const isValidNewBlock = (newBlock, previousBlock) => {
if (previousBlock.index + 1 !== newBlock.index) {
return false;
}
if (previousBlock.hash !== newBlock.previousHash) {
return false;
}
if (calculateHashForBlock(newBlock) !== newBlock.hash) {
return false;
}
return true;
};

49. BLOCK VALIDATION
const isValidNewBlock = (newBlock, previousBlock) => {
if (previousBlock.index + 1 !== newBlock.index) {
return false;
}
if (previousBlock.hash !== newBlock.previousHash) {
return false;
}
if (calculateHashForBlock(newBlock) !== newBlock.hash) {
return false;
}
return true;
};

50. ADDING BLOCK TO CHAIN
class Chain {
(…)
add(newBlock) {
if (isValidNewBlock(newBlock, this.latestBlock())) {
this.blockchain.push(newBlock)
}
return {
'type': RESPONSE_BLOCKCHAIN,
‘data':[latestBlock()]}
}
}
latestBlock () {return last(this.blockchain)};
};

51. TEXT
Hash #0
Genesis Block
Hash #1
PrevHash #0
Hash #2
PrevHash #1
BLOCKCHAIN

52. ADDING BLOCK TO CHAIN
class Chain {
(…)
add(newBlock) {
if (isValidNewBlock(newBlock, this.latestBlock())) {
this.blockchain.push(newBlock)
}
return {
'type': RESPONSE_BLOCKCHAIN,
‘data':[latestBlock()]}
}
}
latestBlock () {return last(this.blockchain)};
};

53. TEXT
New Block
New Block

54. NEW BLOCK HANDLING
const handleBlockchainResponse = (message) => {
const receivedBlocks = message;
if (last(receivedBlocks).index > chain.latestBlock().index) {
if (last(receivedBlocks).previousHash === chain.latestBlock().hash) {
chain.add(latestBlockReceived);
return {'type': RESPONSE_BLOCKCHAIN, ‘data':[chain.latestBlock()]}
}
return {'type': EXCHANGE_CHAINS};
}
};

55. NEW BLOCK HANDLING
const handleBlockchainResponse = (message) => {
const receivedBlocks = message;
if (last(receivedBlocks).index > chain.latestBlock().index) {
if (last(receivedBlocks).previousHash === chain.latestBlock().hash) {
chain.add(latestBlockReceived);
return {'type': RESPONSE_BLOCKCHAIN, ‘data':[chain.latestBlock()]}
}
return {'type': EXCHANGE_CHAINS};
}
};

56. NEW BLOCK HANDLING
const handleBlockchainResponse = (message) => {
const receivedBlocks = message;
if (last(receivedBlocks).index > chain.latestBlock().index) {
if (last(receivedBlocks).previousHash === chain.latestBlock().hash) {
chain.add(latestBlockReceived);
return {'type': RESPONSE_BLOCKCHAIN, ‘data':[chain.latestBlock()]}
}
return {'type': EXCHANGE_CHAINS};
}
};

57. NEW BLOCK HANDLING
const handleBlockchainResponse = (message) => {
const receivedBlocks = message;
if (last(receivedBlocks).index > chain.latestBlock().index) {
if (last(receivedBlocks).previousHash === chain.latestBlock().hash) {
chain.add(latestBlockReceived);
return {'type': RESPONSE_BLOCKCHAIN, ‘data':[chain.latestBlock()]}
}
return {'type': EXCHANGE_CHAINS};
}
};

58. TEXT
Hash #2
EXCHANGE CHAINS

59. TEXT
New Chain
New Chain

60. REPLACING CHAIN
const replaceChain = (newChain) => {
if (newChain.isValidChain() &&
newChain.size() > this.chain.size()){
this.chain = newBlockchain;
return {
'type': RESPONSE_BLOCKCHAIN,
‘data':[chain.latestBlock()]}
}
};

61. REPLACING CHAIN
const replaceChain = (newChain) => {
if (newChain.isValidChain() &&
newChain.size() > this.chain.size()){
this.chain = newBlockchain;
return {
‘type': RESPONSE_BLOCKCHAIN,
‘data’: [chain.latestBlock()]}
}
};

62. REPLACING CHAIN
const replaceChain = (newChain) => {
if (newChain.isValidChain() &&
newChain.size() > this.chain.size()){
this.chain = newBlockchain;
return {
'type': RESPONSE_BLOCKCHAIN,
‘data':[chain.latestBlock()]}
}
};

63. VALIDATING CHAIN
isValidChain () {
if (!isEqual(this.genesisBlock(), GenesisBlock())) {
return false;
}
for (let i = 1; i < this.size(); i++) {
if (!isValidNewBlock(this.get(i), this.get[i - 1])) {
return false;
}
}
return true;
};

64. VALIDATING CHAIN
isValidChain () {
if (!isEqual(this.genesisBlock(), GenesisBlock())) {
return false;
}
for (let i = 1; i < this.size(); i++) {
if (!isValidNewBlock(this.get(i), this.get[i - 1])) {
return false;
}
}
return true;
};

65. VALIDATING CHAIN
isValidChain () {
if (!isEqual(this.genesisBlock(), GenesisBlock())) {
return false;
}
for (let i = 1; i < this.size(); i++) {
if (!isValidNewBlock(this.get(i), this.get[i - 1])) {
return false;
}
}
return true;
};

66. REPLACING CHAIN
const replaceChain = (newChain) => {
if (newChain.isValidChain() &&
newChain.size() > this.chain.size()){
this.chain = newBlockchain;
return {
'type': RESPONSE_BLOCKCHAIN,
‘data':[chain.latestBlock()]}
}
};

67. TEXT
LONGER HASH WINS

68. TEXT
SPINNING NEW BLOCKS

69. PROOF-OF-WORK

70. PROOF-OF-WORK
const calculateHash = (index, prevHash, data) => {
let nonce = 0;
while(true){
nonce++;
seed = `${index} ${prevHash} ${data} ${nonce}`
const value = CryptoJS.SHA256(seed)
if (startsWith(value, "000000")) {
return value;
}
}
};

71. PROOF-OF-WORK
const calculateHash = (index, prevHash, data) => {
let nonce = 0;
while(true){
nonce++;
seed = `${index} ${prevHash} ${data} ${nonce}`
const value = CryptoJS.SHA256(seed)
if (startsWith(value, "000000")) {
return value;
}
}
};

72. PROOF-OF-WORK
const calculateHash = (index, prevHash, data) => {
let nonce = 0;
while(true){
nonce++;
seed = `${index} ${prevHash} ${data} ${nonce}`
const value = CryptoJS.SHA256(seed)
if (startsWith(value, "000000")) {
return value;
}
}
};

73. PROOF-OF-WORK
const calculateHash = (index, prevHash, data) => {
let nonce = 0;
while(true){
nonce++;
seed = `${index} ${prevHash} ${data} ${nonce}`
const value = CryptoJS.SHA256(seed)
if (startsWith(value, "000000")) {
return value;
}
}
};

74. PROOF-OF-WORK
const calculateHash = (index, prevHash, data) => {
let nonce = 0;
while(true){
nonce++;
seed = `${index} ${prevHash} ${data} ${nonce}`
const value = CryptoJS.SHA256(seed)
if (startsWith(value, "000000")) {
return value;
}
}
};

75. PROOF-OF-WORK
const calculateHash = (index, prevHash, data) => {
let nonce = 0;
while(true){
nonce++;
seed = `${index} ${prevHash} ${data} ${nonce}`
const value = CryptoJS.SHA256(seed)
if (startsWith(value, "000000")) {
return value;
}
}
};

76. PROOF-OF-WORK
const calculateHash = (index, prevHash, data) => {
let nonce = 0;
while(true){
nonce++;
seed = `${index} ${prevHash} ${data} ${nonce}`
const value = CryptoJS.SHA256(seed)
if (startsWith(value, "000000")) {
return value;
}
}
};

77. PROOF-OF-WORK
const calculateHash = (index, prevHash, data) => {
let nonce = 0;
while(true){
nonce++;
seed = `${index} ${prevHash} ${data} ${nonce}`
const value = CryptoJS.SHA256(seed)
if (startsWith(value, "000000")) {
return value;
}
}
};

78. TEXT
IDEAL HASH FUNCTION
f( )
f( )?

79. TEXT
I HAVE HASH! 000004CEEF5782B82C212CE725F15594!
00000ee187308970bb63446f3f910e98000004ceef5782b82c212ce725f15594

80. TEXT
Hash #0 Hash #1 Hash #2
SECURITY
Hash #0
Hash #1
Prev #0
Hash #2
Prev #1
Hash #3
Prev #2
Hash #4
Prev #3
Hash #1x
Hash #2x
Prev #1x
Hash #3x
Prev #2x
FORK

81. ▸ =
50% OF WHOLE NETWORK

82. TEXT
BLOCKCHAIN
Hash #1
Prev #2
Hash #2
Prev #3
Hash #0
Prev #1
Hash #0
$ $ $

83. TEXT
PROBLEMS

84. TEXT
ENVIRONMENTAL UNFRIENDLY

85. TEXT
> ENERGY USAGE ICELAND

86. PROOF-OF-STAKE
PRIMECOIN

87. TEXT
SCALABILITY ISSUES

88. TEXT
VERTICAL SCALING HORIZONTAL SCALING

89. TEXT
VERTICAL SCALING

90. TEXT
HORIZANTAL SCALING

91. PROOF-OF-STAKE
DIRECT ACYCLIC GRAPH
LIGHTNING NETWORKS

92. TEXT
SMART CONTRACTS
INITIAL COIN OFFERINGS
SOFT & HARD FORKS

93. TEXT
DNS
IOT
SMART
CONTRACT

94. TEXT

95. THANK YOU AND
WAITING FOR
QUESTIONS
@ArturSkowronski
arturskowronski.com