Online PHP editor | refs for iqUn3

<?php class Block { public $nonce; public function __construct($index, $timestamp, $data, $previousHash = null) { $this->index = $index; $this->timestamp = $timestamp; $this->data = $data; $this->previousHash = $previousHash; $this->hash = $this->calculateHash(); $this->nonce = 0; } public function calculateHash() { return hash("sha256", $this->index.$this->previousHash.$this->timestamp.((string)$this->data).$this->nonce); } } class BlockChain { /** * Instantiates a new Blockchain. */ public function __construct() { $this->chain = [$this->createGenesisBlock()]; $this->difficulty = 4; } /** * Creates the genesis block. */ private function createGenesisBlock() { return new Block(0, strtotime("2017-01-01"), "Genesis Block"); } /** * Gets the last block of the chain. */ public function getLastBlock() { return $this->chain[count($this->chain)-1]; } /** * Pushes a new block onto the chain. */ public function push($block) { $block->previousHash = $this->getLastBlock()->hash; $this->mine($block); array_push($this->chain, $block); } /** * Mines a block. */ public function mine($block) { while (substr($block->hash, 0, $this->difficulty) !== str_repeat("0", $this->difficulty)) { $block->nonce++; $block->hash = $block->calculateHash(); } echo "Block mined: ".$block->hash."\n"; } /** * Validates the blockchain's integrity. True if the blockchain is valid, false otherwise. */ public function isValid() { for ($i = 1; $i < count($this->chain); $i++) { $currentBlock = $this->chain[$i]; $previousBlock = $this->chain[$i-1]; if ($currentBlock->hash != $currentBlock->calculateHash()) { return false; } if ($currentBlock->previousHash != $previousBlock->hash) { return false; } } return true; } } /* Set up a simple chain and mine two blocks. */ $testCoin = new BlockChain(); echo "mining block 1...\n"; $testCoin->push(new Block(1, strtotime("now"), "amount: 4")); echo "mining block 2...\n"; $testCoin->push(new Block(2, strtotime("now"), "amount: 10")); echo json_encode($testCoin, JSON_PRETTY_PRINT);