128 lines
3.7 KiB
Swift
128 lines
3.7 KiB
Swift
//
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// Blockchain.swift
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// Blockchain
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//
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// Created by Victor BODINAUD on 27/02/2020.
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// Copyright © 2020 Victor BODINAUD. All rights reserved.
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//
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import Foundation
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public class Blockchain {
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var chain = [Block]()
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let minDifficulty = 2
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let maxDifficulty = 6
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let targetBlockTime = 10.0 // en secondes
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static let genesisBlock: Block = {
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let block = Block()
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block.previousHash = "0000genesis0000"
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block.index = 0
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block.timestamp = 1701388800
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block.difficulty = 4
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block.nonce = 12345
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block.hash = "000088c1731bed4996680d2c50ea3d9b573c1507d2d61866c0deff33a7f8cf5e"
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return block
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}()
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init() {
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chain.append(Blockchain.genesisBlock)
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print("Genesis block initialized -- hash: \(Blockchain.genesisBlock.hash)")
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}
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func calculateNewDifficulty() -> Int {
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guard chain.count >= 2 else { return minDifficulty }
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let lastBlock = chain.last!
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let previousBlock = chain[chain.count - 2]
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let timeSpent = Double(lastBlock.timestamp - previousBlock.timestamp)
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if timeSpent < targetBlockTime / 2 {
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return min(lastBlock.difficulty + 1, maxDifficulty)
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} else if timeSpent > targetBlockTime * 2 {
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return max(lastBlock.difficulty - 1, minDifficulty)
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}
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return lastBlock.difficulty
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}
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func validateChain(_ chain: [Block]) -> Bool {
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guard let firstBlock = chain.first,
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firstBlock.hash == Blockchain.genesisBlock.hash
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else {
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print("Genesis block mismatch")
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return false
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}
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for i in 1..<chain.count {
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let block = chain[i]
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let previousBlock = chain[i - 1]
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if block.previousHash != previousBlock.hash {
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print("Invalid chain at block \(i): incorrect previous hash")
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return false
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}
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if !block.isValid() {
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print("Invalid chain at block \(i): invalid block hash")
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return false
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}
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}
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return true
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}
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func validateChainTotally(_ chain: [Block]) -> Bool {
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// Vérifier le genesis block
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guard let firstBlock = chain.first,
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firstBlock.hash == Blockchain.genesisBlock.hash
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else {
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print("Chain: Invalid genesis block")
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return false
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}
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// Vérifier la séquence des blocs
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for i in 1..<chain.count {
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let block = chain[i]
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let previousBlock = chain[i - 1]
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// Vérifier le chaînage
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if block.previousHash != previousBlock.hash {
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print("Chain: Invalid block sequence at height \(i)")
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return false
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}
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// Vérifier l'index
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if block.index != i {
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print("Chain: Invalid block index at height \(i)")
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return false
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}
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// Vérifier la chronologie
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if block.timestamp <= previousBlock.timestamp {
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print("Chain: Invalid timestamp at height \(i)")
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return false
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}
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// Vérifier la difficulté
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let expectedDifficulty = calculateExpectedDifficulty(at: i, chain: chain)
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if block.difficulty != expectedDifficulty {
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print("Chain: Invalid difficulty at height \(i)")
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return false
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}
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// Vérifier le bloc lui-même
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if !block.isValid() {
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print("Chain: Invalid block at height \(i)")
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return false
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}
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}
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return true
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}
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private func calculateExpectedDifficulty(at index: Int, chain: [Block]) -> Int {
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return chain[index].difficulty
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}
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}
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