.Net Core搭建区块链，实现比特币流转逻辑

缘起

一直对区块链很感兴趣，但是又感觉一头雾水，这两天特地研究了下比特币的底层逻辑，豁然开朗。

区块链

区块链其实没那么复杂，其实就是一种链表存储结构，该链表的最小单位是区块

区块主要包含区块高度、上个区块Hash值、区块存储数据、区块创建时间、区块Hash值、随机数

Hash值是通过一定算法，对当前区块其他属性值进行签名得到

区块之间首尾相连，当前区块会存储上个区块的Hash值，同时当前区块的Hash值的计算依赖上个区块的Hash值，因此，最终形成的区块链将变得非常敏感，但凡有一个区块的数据被篡改，后面区块的Hash值将不符合链表规则，无法校验通过，因此可以大幅提升数据的可信度。

去中心化

区块链技术中，去中心化也是一个重要概念，每个拥有某个区块链的用户，都将持续化存储该区块链全部信息到本地，也即每个用户都拥有完整的区块链数据库。

项目

项目地址

https://github.com/Rhyheart/drea-block-chain

区块实体

public class Block
    {
        public Block(long index, string previousHash, List<Record> data)
        {
            Index = index;
            PreviousHash = previousHash;
            Data = data;
            TimeStamp = DateTime.Now;
            Nonce = Guid.NewGuid().ToString("N");
            Hash = CalculateHash();
        }

        /// <summary>
        /// 索引，区块高度
        /// </summary>
        public long Index { get; set; }

        /// <summary>
        /// 上个区块Hash值
        /// </summary>
        public string PreviousHash { get; set; }

        /// <summary>
        /// 当前区块存储的数据
        /// </summary>
        public List<Record> Data { get; set; }

        /// <summary>
        /// 区块创建时间
        /// </summary>
        public DateTime TimeStamp { get; set; }

        /// <summary>
        /// 随机数，用于改变Hash值，让其符合创世人设定的规则
        /// </summary>
        public string Nonce { get; set; }

        /// <summary>
        /// 当前区块Hash值
        /// </summary>
        public string Hash { get; set; }

        /// <summary>
        /// 计算Hash值
        /// </summary>
        /// <returns></returns>
        public string CalculateHash()
        {
            var sha256 = SHA256.Create();

            var inputBytes = Encoding.ASCII.GetBytes($"{PreviousHash}-{Data}-{TimeStamp}-{Nonce}");
            var outputBytes = sha256.ComputeHash(inputBytes);

            return Convert.ToBase64String(outputBytes);
        }
    }

数据实体

 public class Record
    {
        /// <summary>
        /// 转账人
        /// </summary>
        public string Sender { get; set; }

        /// <summary>
        /// 收账人
        /// </summary>
        public string Receiver { get; set; }

        /// <summary>
        /// 金额
        /// </summary>
        public decimal Amount { get; set; }
    }

链服务

public class BlockChainService
    {
        public IList<Block> Chain { set; get; }

        public BlockChainService()
        {
            InitializeChain();
        }

        /// <summary>
        /// 初始化区块链
        /// </summary>
        public void InitializeChain()
        {
            Chain = new List<Block>();
        }

        /// <summary>
        /// 添加创世区块
        /// </summary>
        /// <param name="records"></param>
        public void AddGenesisBlock(List<Record> records)
        {
            Chain.Add(new Block(0, "", records));
        }

        /// <summary>
        /// 获取最新区块
        /// </summary>
        /// <returns></returns>
        public Block GetLatestBlock()
        {
            return Chain.Last();
        }

        /// <summary>
        /// 添加区块
        /// </summary>
        /// <param name="records"></param>
        public void AddBlock(List<Record> records)
        {
            var latestBlock = GetLatestBlock();
            Chain.Add(new Block(latestBlock.Index + 1, latestBlock.Hash, records));
        }

        /// <summary>
        /// 验证当前区块链数据是否合规
        /// </summary>
        /// <returns></returns>
        public bool IsValid()
        {
            if (Chain[0].Hash != Chain[0].CalculateHash())
            {
                return false;
            }

            for (var i = 1; i < Chain.Count; i++)
            {
                var currentBlock = Chain[i];
                var previousBlock = Chain[i - 1];

                if (currentBlock.Hash != currentBlock.CalculateHash())
                {
                    return false;
                }

                if (currentBlock.PreviousHash != previousBlock.Hash)
                {
                    return false;
                }
            }
            return true;
        }
    }

入口方法

using Drea.BlockChain;
using Newtonsoft.Json;

var blockChainService = new BlockChainService();

#region 创世区块

Console.WriteLine("创世人 Rhyheart 创建了区块链，开始添加创世区块...");

var records = new List<Record>
{
    new Record
    {
        Sender = "System",
        Receiver = "Rhyheart",
        Amount = 50
    }
};

blockChainService.AddGenesisBlock(records);

Console.WriteLine("创世区块添加成功，创世人 Rhyheart 获得系统奖励的 50 个虚拟货币");
Console.WriteLine();

#endregion

#region 第二区块

Console.WriteLine("交易进行中...");

var records2 = new List<Record>
{
    new Record
    {
        Sender = "Rhyheart",
        Receiver = "Mark",
        Amount = 5
    },
    new Record
    {
        Sender = "Rhyheart",
        Receiver = "Frank",
        Amount = 5
    },
    new Record
    {
        Sender = "Rhyheart",
        Receiver = "Mark",
        Amount = 10
    },
    new Record
    {
        Sender = "Rhyheart",
        Receiver = "Jack",
        Amount = 5
    },
    new Record
    {
        Sender = "Mark",
        Receiver = "Rhyheart",
        Amount = 5
    }
};

Console.WriteLine("产生了 5 笔新交易，符合区块打包规则，用户们开始争夺第二区块添加权...");

Console.WriteLine("用户 Frank 争夺成功，获得区块添加权，开始添加第二区块...");

blockChainService.AddBlock(records2);

Console.WriteLine("第二区块添加成功，用户 Frank 获得系统奖励的 50 个虚拟货币");

Console.WriteLine();

#endregion

#region 第三区块

Console.WriteLine("交易进行中...");

var records3 = new List<Record>
{
    new Record
    {
        Sender = "System",
        Receiver = "Frank",
        Amount = 50
    },
    new Record
    {
        Sender = "Frank",
        Receiver = "Mark",
        Amount = 5
    },
    new Record
    {
        Sender = "Mark",
        Receiver = "Frank",
        Amount = 5
    },
    new Record
    {
        Sender = "Frank",
        Receiver = "Mark",
        Amount = 10
    },
    new Record
    {
        Sender = "Frank",
        Receiver = "Jack",
        Amount = 5
    },
    new Record
    {
        Sender = "Mark",
        Receiver = "Rhyheart",
        Amount = 5
    }
};

Console.WriteLine("产生了 5 笔新交易，符合区块打包规则，用户们开始争夺第三区块添加权...");

Console.WriteLine("用户 Mark 争夺成功，获得区块添加权，开始添加第三区块...");

blockChainService.AddBlock(records3);

Console.WriteLine("第二区块添加成功，用户 Mark 获得系统奖励的 50 个虚拟货币");

Console.WriteLine();

#endregion

Console.WriteLine($"区块链数据验证：{blockChainService.IsValid()}");
Console.WriteLine();

var totalAmount = blockChainService.Chain.Sum(x => x.Data.Where(x => x.Sender == "System").Sum(y => y.Amount));
Console.WriteLine($"区块链总虚拟货币数：{totalAmount}");
Console.WriteLine();

var receiveAmount = blockChainService.Chain.Sum(x => x.Data.Where(x => x.Receiver == "Rhyheart").Sum(y => y.Amount));
var sendAmount = blockChainService.Chain.Sum(x => x.Data.Where(x => x.Sender == "Rhyheart").Sum(y => y.Amount));
var amount = receiveAmount - sendAmount;
Console.WriteLine($"区块链 Rhyheart 用户虚拟货币余额：{amount}");
Console.WriteLine();

var chain = JsonConvert.SerializeObject(blockChainService.Chain);
Console.WriteLine($"区块链详情：{chain}");
Console.WriteLine();