沧海一粟

<?php
/**
* 区块链相关算法
*/
class Block
{
    
    public $timestamp; //时间
  
    public $index; //索引
    
    public $data; //数据

    public $prevHash; //上一个哈希值
    
    public $hash; //当前哈希值

    public function __construct($index, $timestamp, $data, $prevHash = '')
    {
        $this->index = $index;
        $this->timestamp = $timestamp;
        $this->data = $data;
        $this->prevHash = $prevHash;
        $this->hash = $this->calculateHash();
    }
    /**
     * 加密算法
     * @return string
     */
    public function calculateHash()
    {
        return hash('sha256', $this->index . $this->prevHash . $this->timestamp . json_encode($this->data));
    }
}
/**
* 区块链
* Class BlockChain
*/
class BlockChain
{

    public $chain = []; // Block[]

    public function __construct()
    {
        $this->chain = [$this->createGenesisBlock()];
    }
    /**
     * 创世区块
     * @return Block
     */
    public function createGenesisBlock()
    {
        return new Block(0, '2017-01-23', 'forecho', '0');
    }
    /**
     * 获取最新的区块
     * @return Block|mixed
     */
    public function getLatestBlock()
    {
        return $this->chain[count($this->chain) - 1];
    }
    /**
     * 添加区块
     * @param Block $newBlock
     */
    public function addBlock(Block $newBlock)
    {
        $newBlock->prevHash = $this->getLatestBlock()->hash;
        $newBlock->hash = $newBlock->calculateHash();
        array_push($this->chain, $newBlock);
    }
    /**
     * 验证区块链
     * @return bool
     */
    public function isChainValid()
    {
        for ($i = 1; $i < count($this->chain); $i++) {
            $currentBlock = $this->chain[$i];
            $prevBlock = $this->chain[$i - 1];
            if ($currentBlock->hash !== $currentBlock->calculateHash()) {
                return false;
            }
            if ($currentBlock->prevHash !== $prevBlock->hash) {
                return false;
            }
        }
        return true;
    }
}
// test
$blockChain = new BlockChain();
$blockChain->addBlock(new Block(1, '2017-02-23', ['amount' => 1]));
$blockChain->addBlock(new Block(2, '2017-03-23', ['amount' => 3]));
$blockChain->addBlock(new Block(3, '2017-04-23', ['amount' => 20]));
print_r($blockChain);
echo "区块链验证通过吗？" . ($blockChain->isChainValid() ? '通过' : '失败') . PHP_EOL;
$blockChain->chain[1]->data = ['amount' => 2];
$blockChain->chain[1]->hash = $blockChain->chain[1]->calculateHash();
echo "区块链验证通过吗？" . ($blockChain->isChainValid() ? '通过' : '失败') . PHP_EOL;