文章目录

  • 前言
  • 一、区块链的实现
    • 1.定义区块模型
    • 2.管理区块链
    • 3.使用区块链

前言

区块链是一种分布式数据库，使用密码学技术进行安全的数据记录和验证。它可以被用来创建可信赖的记录，并确保记录不可篡改。区块链的原理其实是一个又一个区块组成的链条。每一个区块中保存了一定的信息，它们按照各自产生的时间顺序连接成链条。这个链条被保存在所有的服务器中，只要整个系统中有一台服务器可以工作，整条区块链就是安全的。这些服务器在区块链系统中被称为节点，它们为整个区块链系统提供存储空间和算力支持。如果要修改区块链中的信息，必须征得半数以上节点的同意并修改所有节点中的信息，而这些节点通常掌握在不同的主体手中，因此篡改区块链中的信息是一件极其困难的事。相比于传统的网络，区块链具有两大核心特点：一是数据难以篡改、二是去中心化。基于这两个特点，区块链所记录的信息更加真实可靠，可以帮助解决人们互不信任的问题。

一、区块链的实现

1.定义区块模型

/// <summary>/// 区块数据模型/// </summary>public struct Block{/// <summary>/// 区块位置/// </summary>public int Index { get; set; }/// <summary>/// 区块生成时间戳/// </summary>public string TimeStamp { get; set; } /// <summary>/// 心率数值/// </summary>public int BPM { get; set; }/// <summary>/// 区块 SHA-256 散列值/// </summary>public string Hash { get; set; }/// <summary>/// 前一个区块 SHA-256 散列值/// </summary>public string PrevHash { get; set; }}

2.管理区块链

/// <summary>/// 管理区块链/// </summary>public static class BlockGenerator{public static List<Block> _blockChain = new List<Block>();/// <summary>/// 计算区块 HASH 值/// </summary>/// <param name="block">区块实例</param>/// <returns>计算完成的区块散列值</returns>public static string CalculateHash(Block block){string calculationStr = $"{block.Index}{block.TimeStamp}{block.BPM}{block.PrevHash}";SHA256 sha256Generator = SHA256.Create();byte[] sha256HashBytes = sha256Generator.ComputeHash(Encoding.UTF8.GetBytes(calculationStr));StringBuilder sha256StrBuilder = new StringBuilder();foreach (byte @byte in sha256HashBytes){sha256StrBuilder.Append(@byte.ToString("x2"));}return sha256StrBuilder.ToString();}/// <summary>/// 生成新的区块/// </summary>/// <param name="oldBlock">旧的区块数据</param>/// <param name="BPM">心率</param>/// <returns>新的区块</returns>public static Block GenerateBlock(Block oldBlock, int BPM){Block newBlock = new Block(){Index = oldBlock.Index + 1,TimeStamp = CalculateCurrentTimeUTC(),BPM = BPM,PrevHash = oldBlock.Hash};newBlock.Hash = CalculateHash(newBlock);return newBlock;}/// <summary>/// 计算当前时间的 UTC 表示格式/// </summary>/// <returns>UTC 时间字符串</returns>public static string CalculateCurrentTimeUTC(){DateTime startTime = new DateTime(1970, 1, 1, 0, 0, 0, 0);DateTime nowTime = DateTime.Now;long unixTime = (long)Math.Round((nowTime - startTime).TotalMilliseconds, MidpointRounding.AwayFromZero);return unixTime.ToString();}/// <summary>/// 检验区块是否有效/// </summary>/// <param name="newBlock">新生成的区块数据</param>/// <param name="oldBlock">旧的区块数据</param>/// <returns>有效返回 TRUE，无效返回 FALSE</returns>public static bool IsBlockValid(Block newBlock, Block oldBlock){if (oldBlock.Index + 1 != newBlock.Index) return false;if (oldBlock.Hash != newBlock.PrevHash) return false;if (CalculateHash(newBlock) != newBlock.Hash) return false;return true;}/// <summary>/// 如果新的区块链比当前区块链更新，则切换当前区块链为最新区块链/// </summary>/// <param name="newBlockChain">新的区块链</param>public static void SwitchChain(List<Block> newBlockChain){if (newBlockChain.Count > _blockChain.Count){_blockChain = newBlockChain;}}}

3.使用区块链

1、webapi相关代码

[ApiController][Route("[controller]/[action]")]public class HomeController : ControllerBase{private readonly ILogger<HomeController> _logger;public HomeController(ILogger<HomeController> logger){_logger = logger;}/// <summary>/// 设置10个区块/// </summary>/// <param name="bpm"></param>/// <returns></returns>[HttpPost][Route("/BlockChain")]public string BlockChain(int bpm){// 增加区块链if (BlockGenerator._blockChain.Count == 0){Block firstBlock = new Block(){Index = 0,TimeStamp = BlockGenerator.CalculateCurrentTimeUTC(),BPM = 0,Hash = string.Empty,PrevHash = string.Empty};BlockGenerator._blockChain.Add(firstBlock);return JsonConvert.SerializeObject(firstBlock);}else{Block oldBlock = BlockGenerator._blockChain.Last();Block newBlock = BlockGenerator.GenerateBlock(oldBlock, bpm);if (BlockGenerator.IsBlockValid(newBlock, oldBlock)){List<Block> newBlockChain = new List<Block>();foreach (var block in BlockGenerator._blockChain){newBlockChain.Add(block);}newBlockChain.Add(newBlock);BlockGenerator.SwitchChain(newBlockChain);}return JsonConvert.SerializeObject(newBlock);}}//提取区块链[HttpGet][Route("/BlockChains")]public string Validate(){return JsonConvert.SerializeObject(BlockGenerator._blockChain);}}


2、运行

[{"Index": 0,"TimeStamp": "1676908972475","BPM": 0,"Hash": "","PrevHash": ""}, {"Index": 1,"TimeStamp": "1676908974139","BPM": 1,"Hash": "fb3fdd06a2175b8531b44680ebbd846a080ba3262819bff8e78fd8fdb37ae5cb","PrevHash": ""}, {"Index": 2,"TimeStamp": "1676908975705","BPM": 2,"Hash": "c15d7d8f13cc0a74922ab7435df72c79751bf642c7636d839b41a047c257f9f5","PrevHash": "fb3fdd06a2175b8531b44680ebbd846a080ba3262819bff8e78fd8fdb37ae5cb"}, {"Index": 3,"TimeStamp": "1676908980354","BPM": 3,"Hash": "1a9da938bf89d57b3ee18a62b79b9be41424c2552dd1d0bfa15038be4faae504","PrevHash": "c15d7d8f13cc0a74922ab7435df72c79751bf642c7636d839b41a047c257f9f5"}, {"Index": 4,"TimeStamp": "1676908981790","BPM": 4,"Hash": "e37b72244f41ecdef2da0ef5ede0971560eec9a5144d935ac74f2ea9ece44b8e","PrevHash": "1a9da938bf89d57b3ee18a62b79b9be41424c2552dd1d0bfa15038be4faae504"}, {"Index": 5,"TimeStamp": "1676908983222","BPM": 5,"Hash": "87a91f780299618510befed23da583af035147f21f51e21866d2d0ad412485ee","PrevHash": "e37b72244f41ecdef2da0ef5ede0971560eec9a5144d935ac74f2ea9ece44b8e"}, {"Index": 6,"TimeStamp": "1676908984659","BPM": 6,"Hash": "960d8fb0f6c77a20a1b26a870f5a43489f39b2a22b382f413cb870d446afaecc","PrevHash": "87a91f780299618510befed23da583af035147f21f51e21866d2d0ad412485ee"}]

可以看到生成7个区块链就像链条一样头尾相连。