Blockchain: Developer's Perspective (Java Edition)
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The document discusses the complexities and technical aspects of blockchain technology from both developer and investor perspectives, including Bitcoin and concepts like double spending and decentralized trust. It includes coding examples for blockchain structure, hashing, block validation, and block mining processes. Additionally, it touches on scalability issues, energy consumption, and potential solutions such as proof-of-stake and lightning networks.
Blockchain: Developer's Perspective (Java Edition)
- 2. TEXT HOW TO BECOME RICH INVESTOR’S PERSPECTIVE
- 4. BITCOINAIRE
- 5. MtGox Fraud Initial Whitepaper Original Peak WTF?
- 8. TEXT George Soros LIBERTARIANS KILL THE BANKS AND BANKERS
- 11. TEXT
- 12. TEXT
- 13. TEXT
- 14. BLOCKCHAIN
- 17. DOUBLE SPENDING
- 19. ?
- 21. TEXT LEDGER
- 22. CENTRALISED
- 23. TEXT TRUST
- 26. POLITICALLY DECENTRALISED ARCHITECTURALLY DECENTRALISED LOGICALLY DECENTRALISED
- 28. TEXT …USING MATH
- 29. TEXT LET’S CODEBASED ON NAIVECHAIN BY @LHARTIKK @ARTURSKOWRONSKI/NAIVECHAIN-JAVA
- 30. TEXT P2P (WebSockets) P2P (WebSockets) P2P (WebSockets)
- 31. public class Block { protected int index; protected String hash; protected String previousHash; protected long timestamp; protected Object data; protected int nonce; } BLOCK PART
- 32. BLOCK PART public class Block { protected int index; protected String hash; protected String previousHash; protected long timestamp; protected Object data; protected int nonce; }
- 33. BLOCK PART public class Block { protected int index; protected String hash; protected String previousHash; protected long timestamp; protected Object data; protected int nonce; }
- 34. BLOCK PART public class Block { protected int index; protected String hash; protected String previousHash; protected long timestamp; protected Object data; protected int nonce; }
- 35. BLOCK PART public class Block { protected int index; protected String hash; protected String previousHash; protected long timestamp; protected Object data; protected int nonce; }
- 36. CHAIN PART public class Blockchain extends LinkedList<Block> { public Blockchain(Block block) { this.add(GENESIS_BLOCK); } }
- 37. CHAIN PART public class Blockchain extends LinkedList<Block> { public Blockchain(Block block) { this.add(GENESIS_BLOCK); } }
- 38. CHAIN PART public class Blockchain extends LinkedList<Block> { public Blockchain(Block block) { this.add(GENESIS_BLOCK); } }
- 39. CHAIN PART public class Blockchain extends LinkedList<Block> { public Blockchain(Block block) { this.add(GENESIS_BLOCK); } }
- 40. GENESIS BLOCK public static final Block GENESIS_BLOCK = new Block( 0, //index “e6337db8a921823784c14378abed4f7d7", //hash null, //previousHash 1465154705, //timestamp "Pozdro Bielsko-Biala!”, //data 0 //nonce );
- 41. MINING BLOCK public class BlockchainService { Blockchain chain = new Blockchain(); public Block mineBlock(Object data) => { Block newBlock = nextBlock(chain.getLast(), data); chain.addBlock(newBlock); return chain.getLast(); }; }
- 42. MINING BLOCK public class BlockchainService { Blockchain chain = new Blockchain(); public Block mineBlock(Object data) => { Block newBlock = nextBlock(chain.getLast(), data); chain.addBlock(newBlock); return chain.getLast(); }; }
- 43. MINING BLOCK public class BlockchainService { Blockchain chain = new Blockchain(); public Block mineBlock(Object data) => { Block newBlock = nextBlock(chain.getLast(), data); chain.addBlock(newBlock); return chain.getLast(); }; }
- 44. MINING BLOCK public static Block nextBlock(Block prevBlock, Object data) { int nextIndex = previousBlock.index + 1; String prevHash = prevBlock.getHash(); long nextTime = new Date().getTime(); String nextHash = calculateHash(nextIndex, prevHash, nextTime, data); return new Block(nextIndex, prevHash, nextHash, nextTime, data); }
- 45. MINING BLOCK public static Block nextBlock(Block prevBlock, Object data) { int nextIndex = previousBlock.index + 1; String prevHash = prevBlock.getHash(); long nextTime = new Date().getTime(); String nextHash = calculateHash(nextIndex, prevHash, nextTime, data); return new Block(nextIndex, prevHash, nextHash, nextTime, data); }
- 46. MINING BLOCK public static Block nextBlock(Block prevBlock, Object data) { int nextIndex = previousBlock.index + 1; String prevHash = prevBlock.getHash(); long nextTime = new Date().getTime(); String nextHash = calculateHash(nextIndex, prevHash, nextTime, data); return new Block(nextIndex, prevHash, nextHash, nextTime, data); }
- 47. MINING BLOCK public static Block nextBlock(Block prevBlock, Object data) { int nextIndex = previousBlock.index + 1; String prevHash = prevBlock.getHash(); long nextTime = new Date().getTime(); String nextHash = calculateHash(nextIndex, prevHash, nextTime, data); return new Block(nextIndex, prevHash, nextHash, nextTime, data); }
- 48. MINING BLOCK public static Block nextBlock(Block prevBlock, Object data) { int nextIndex = previousBlock.index + 1; String prevHash = prevBlock.getHash(); long nextTime = new Date().getTime(); String nextHash = calculateHash(nextIndex, prevHash, nextTime, data); return new Block(nextIndex, prevHash, nextHash, nextTime, data); }
- 49. CALCULATE HASH private String calculateHash(int index, String prevHash, long ts, Object data) { return sha256Hex(index + prevHash + ts + data.hashCode()); }
- 50. MINING BLOCK public static Block nextBlock(Block prevBlock, Object data) { int nextIndex = previousBlock.index + 1; String prevHash = prevBlock.getHash(); long nextTime = new Date().getTime(); String nextHash = calculateHash(nextIndex, prevHash, nextTime, data); return new Block(nextIndex, prevHash, nextHash, nextTime, data); }
- 51. MINING BLOCK public class BlockchainService { Blockchain chain = new Blockchain(); public Block mineBlock(Object data) => { Block newBlock = nextBlock(chain.getLast(), data); chain.addBlock(newBlock); return chain.getLast(); }; }
- 52. ADDING BLOCK TO CHAIN public class Blockchain extends LinkedList<Block> { (...) public BlockchainResponse addBlock(Block block){ if(isValidNewBlock(getLast(), block)) { add(block); } return new BlockchainResponse(RESPONSE_BLOCKCHAIN, block); } (...) }
- 53. ADDING BLOCK TO CHAIN public class Blockchain extends LinkedList<Block> { (...) public BlockchainResponse addBlock(Block block){ if(isValidNewBlock(getLast(), block)) { add(block); } return new BlockchainResponse(RESPONSE_BLOCKCHAIN, block); } (...) }
- 54. BLOCK VALIDATION public static boolean isValidNewBlock(Block previousBlock, Block newBlock){ if (previousBlock.getIndex() + 1 != newBlock.getIndex()) { return false; } if (!previousBlock.getHash().equals(newBlock.getHash())) { return false; } if (calculateHashForBlock(newBlock).equals(newBlock.getHash())) { return false; } return true; }
- 55. BLOCK VALIDATION public static boolean isValidNewBlock(Block previousBlock, Block newBlock){ if (previousBlock.getIndex() + 1 != newBlock.getIndex()) { return false; } if (!previousBlock.getHash().equals(newBlock.getHash())) { return false; } if (calculateHashForBlock(newBlock).equals(newBlock.getHash())) { return false; } return true; }
- 56. BLOCK VALIDATION public static boolean isValidNewBlock(Block previousBlock, Block newBlock){ if (previousBlock.getIndex() + 1 != newBlock.getIndex()) { return false; } if (!previousBlock.getHash().equals(newBlock.getHash())) { return false; } if (calculateHashForBlock(newBlock).equals(newBlock.getHash())) { return false; } return true; }
- 57. BLOCK VALIDATION public static boolean isValidNewBlock(Block previousBlock, Block newBlock){ if (previousBlock.getIndex() + 1 != newBlock.getIndex()) { return false; } if (!previousBlock.getHash().equals(newBlock.getHash())) { return false; } if (calculateHashForBlock(newBlock).equals(newBlock.getHash())) { return false; } return true; }
- 58. ADDING BLOCK TO CHAIN public class Blockchain extends LinkedList<Block> { (...) public BlockchainResponse addBlock(Block block){ if(isValidNewBlock(getLast(), block)) { add(block); } return new BlockchainResponse(RESPONSE_BLOCKCHAIN, block); } (...) }
- 59. TEXT Hash #0 Genesis Block Hash #1 PrevHash #0 Hash #2 PrevHash #1 BLOCKCHAIN
- 60. ADDING BLOCK TO CHAIN public class Blockchain extends LinkedList<Block> { (...) public Response addBlock(Block block){ if(isValidNewBlock(getLast(), block)) { add(block); } return new Response(RESPONSE_BLOCKCHAIN, block); } (...) }
- 61. TEXT New Block New Block GOSSIP PROTOCOL
- 62. NEW BLOCK HANDLING public Response handleBlockchainResponse(Blockchain newChain) { if (newChain.getLast().getIndex() > chain.getLast().getIndex()) { if (chain.getLast().getHash().equals(newChain.getLast().getPreviousHash())){ chain.addBlock(latestBlockReceived); return new Response(RESPONSE_BLOCKCHAIN, new Blockchain(chain.getLast())); } return exchangeChains(newChain); } return new Response(DO_NOTHING); }
- 63. NEW BLOCK HANDLING public Response handleBlockchainResponse(Blockchain newChain) { if (newChain.getLast().getIndex() > chain.getLast().getIndex()) { if (chain.getLast().getHash().equals(newChain.getLast().getPreviousHash())){ chain.addBlock(latestBlockReceived); return new Response(RESPONSE_BLOCKCHAIN, new Blockchain(chain.getLast())); } return exchangeChains(newChain); } return new Response(DO_NOTHING); }
- 64. NEW BLOCK HANDLING public Response handleBlockchainResponse(Blockchain newChain) { if (newChain.getLast().getIndex() > chain.getLast().getIndex()) { if (chain.getLast().getHash().equals(newChain.getLast().getPreviousHash())){ chain.addBlock(latestBlockReceived); return new Response(RESPONSE_BLOCKCHAIN, new Blockchain(chain.getLast())); } return exchangeChains(newChain); } return new Response(DO_NOTHING); }
- 65. NEW BLOCK HANDLING public Response handleBlockchainResponse(Blockchain newChain) { if (newChain.getLast().getIndex() > chain.getLast().getIndex()) { if (chain.getLast().getHash().equals(newChain.getLast().getPreviousHash())){ chain.addBlock(latestBlockReceived); return new BlockchainResponse(RESPONSE_BLOCKCHAIN, new Blockchain(chain.getLast())); } return exchangeChains(newChain); } return new BlockchainResponse(DO_NOTHING); }
- 67. TEXT New Chain New Chain GOSSIP PROTOCOL
- 68. REPLACING CHAIN private Response exchangeChain(Blockchain newBlockchain) { if (newBlockchain.isValidChain() && newBlockchain.size() > chain.size()) { chain = newBlockchain; return new Response(RESPONSE_BLOCKCHAIN, new Blockchain(chain.getLast())); } else { return new Response(DO_NOTHING); } }
- 69. REPLACING CHAIN private Response exchangeChain(Blockchain newBlockchain) { if (newBlockchain.isValidChain() && newBlockchain.size() > chain.size()) { chain = newBlockchain; return new Response(RESPONSE_BLOCKCHAIN, new Blockchain(chain.getLast())); } else { return new Response(DO_NOTHING); } }
- 70. REPLACING CHAIN private Response exchangeChain(Blockchain newBlockchain) { if (newBlockchain.isValidChain() && newBlockchain.size() > chain.size()) { chain = newBlockchain; return new Response(RESPONSE_BLOCKCHAIN, new Blockchain(chain.getLast())); } else { return new Response(DO_NOTHING); } }
- 71. VALIDATING CHAIN public boolean isValidChain(){ if (!this.getFirst().equals(GENESIS_BLOCK)){ return false; } for (int i = 1; i < this.size() - 1; i++) { if (!Block.isValidNewBlock(this.get(i - 1), this.get(i))){ return false; } } return true; }
- 72. VALIDATING CHAIN public boolean isValidChain(){ if (!this.getFirst().equals(GENESIS_BLOCK)){ return false; } for (int i = 1; i < this.size() - 1; i++) { if (!Block.isValidNewBlock(this.get(i - 1), this.get(i))){ return false; } } return true; }
- 73. VALIDATING CHAIN public boolean isValidChain(){ if (!this.getFirst().equals(GENESIS_BLOCK)){ return false; } for (int i = 1; i < this.size() - 1; i++) { if (!Block.isValidNewBlock(this.get(i - 1), this.get(i))){ return false; } } return true; }
- 74. REPLACING CHAIN private Response exchangeChain(Blockchain newBlockchain) { if (newBlockchain.isValidChain() && newBlockchain.size() > chain.size()) { chain = newBlockchain; return new Response(RESPONSE_BLOCKCHAIN, new Blockchain(chain.getLast())); } else { return new Response(DO_NOTHING); } }
- 77. PROOF-OF-WORK
- 78. PROOF-OF-WORK private static HashPair calculateHash(int index, String previousHash, Object data) { int nonce = 0; while (true) { nonce++; String value = sha256Hex(index + previousHash + data.hashCode() + nonce); if (value.startsWith(“000")) { return new HashPair(nounce, value); } } }
- 79. PROOF-OF-WORK private static HashPair calculateHash(int index, String previousHash, Object data) { int nonce = 0; while (true) { nonce++; String value = sha256Hex(index + previousHash + data.hashCode() + nonce); if (value.startsWith(“000")) { return new HashPair(nounce, value); } } }
- 80. PROOF-OF-WORK private static HashPair calculateHash(int index, String previousHash, Object data) { int nonce = 0; while (true) { nonce++; String value = sha256Hex(index + previousHash + data.hashCode() + nonce); if (value.startsWith(“000")) { return new HashPair(nonce, value); } } }
- 81. PROOF-OF-WORK private static HashPair calculateHash(int index, String previousHash, Object data) { int nonce = 0; while (true) { nonce++; String value = sha256Hex(index + previousHash + data.hashCode() + nonce); if (value.startsWith(“000")) { return new HashPair(nonce, value); } } }
- 82. PROOF-OF-WORK private static HashPair calculateHash(int index, String previousHash, Object data) { int nonce = 0; while (true) { nonce++; String value = sha256Hex(index + previousHash + data.hashCode() + nonce); if (value.startsWith(“000")) { return new HashPair(nonce, value); } } }
- 83. PROOF-OF-WORK private static HashPair calculateHash(int index, String previousHash, Object data) { int nonce = 0; while (true) { nonce++; String value = sha256Hex(index + previousHash + data.hashCode() + nonce); if (value.startsWith(“000")) { return new HashPair(nonce, value); } } }
- 84. PROOF-OF-WORK private static HashPair calculateHash(int index, String previousHash, Object data) { int nonce = 0; while (true) { nonce++; String value = sha256Hex(index + previousHash + data.hashCode() + nonce); if (value.startsWith(“000")) { return new HashPair(nonce, value); } } }
- 85. TEXT IDEAL HASH FUNCTION f( ) f( )?
- 86. TEXT I HAVE HASH! 000004CEEF5782B82C212CE725F15594! 00000ee187308970bb63446f3f910e98000004ceef5782b82c212ce725f15594
- 87. 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
- 88. ▸ = 50% OF WHOLE NETWORK
- 89. TEXT BLOCKCHAIN Hash #1 Prev #2 Hash #2 Prev #3 Hash #0 Prev #1 Hash #0 $ $ $
- 90. TEXT PROBLEMS
- 92. TEXT > ENERGY USAGE ICELAND
- 95. TEXT VERTICAL SCALING HORIZONTAL SCALING
- 98. PROOF-OF-STAKE DIRECT ACYCLIC GRAPH LIGHTNING NETWORKS
- 99. TEXT SMART CONTRACTS INITIAL COIN OFFERINGS SOFT & HARD FORKS
- 101. TEXT
- 102. THANK YOU AND WAITING FOR QUESTIONS @ArturSkowronski arturskowronski.com