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php 实现区块链

2026-02-16 17:48:57PHP

PHP 实现区块链基础

区块链是一种分布式数据库技术，通过加密和共识机制确保数据不可篡改。PHP 可以通过模拟核心概念实现简化版区块链。

区块结构设计

区块通常包含索引（index）、时间戳（timestamp）、数据（data）、前一个区块的哈希（previous_hash）和当前哈希（hash）。以下是一个 PHP 类示例：

class Block {
    public $index;
    public $timestamp;
    public $data;
    public $previous_hash;
    public $hash;

    public function __construct($index, $timestamp, $data, $previous_hash) {
        $this->index = $index;
        $this->timestamp = $timestamp;
        $this->data = $data;
        $this->previous_hash = $previous_hash;
        $this->hash = $this->calculateHash();
    }

    public function calculateHash() {
        return hash('sha256', 
            $this->index . 
            $this->timestamp . 
            $this->data . 
            $this->previous_hash
        );
    }
}

创建区块链

区块链由多个区块组成，首个区块称为创世区块（genesis block）。初始化区块链并添加新区块的示例：

class Blockchain {
    public $chain;

    public function __construct() {
        $this->chain = [$this->createGenesisBlock()];
    }

    private function createGenesisBlock() {
        return new Block(0, time(), "Genesis Block", "0");
    }

    public function getLatestBlock() {
        return $this->chain[count($this->chain) - 1];
    }

    public function addBlock($newBlock) {
        $newBlock->previous_hash = $this->getLatestBlock()->hash;
        $newBlock->hash = $newBlock->calculateHash();
        array_push($this->chain, $newBlock);
    }
}

验证区块链完整性

为确保区块链未被篡改，需验证每个区块的哈希是否匹配且前一个区块的哈希正确：

public function isChainValid() {
    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->previous_hash !== $previousBlock->hash) {
            return false;
        }
    }
    return true;
}

工作量证明（PoW）

为模拟挖矿过程，可以添加简单的工作量证明机制。修改 calculateHash 方法使其包含一个随机数（nonce），直到找到符合特定条件的哈希：

public function calculateHash() {
    $nonce = 0;
    while (true) {
        $hash = hash('sha256', 
            $this->index . 
            $this->timestamp . 
            $this->data . 
            $this->previous_hash . 
            $nonce
        );
        if (substr($hash, 0, 4) === "0000") { // 简单难度条件
            return $hash;
        }
        $nonce++;
    }
}

实际应用示例

创建并测试一个简单的区块链：

$blockchain = new Blockchain();
$blockchain->addBlock(new Block(1, time(), "Transaction Data 1", ""));
$blockchain->addBlock(new Block(2, time(), "Transaction Data 2", ""));

// 输出区块链
print_r($blockchain->chain);

// 验证区块链
echo "Blockchain is valid: " . ($blockchain->isChainValid() ? "Yes" : "No");