1 using System;
  2 using System.Collections.Generic;
  3 using System.Security.Cryptography;
  4 using System.Text;
  5 
  6 namespace TestPrj
  7 {
  8     class Program
  9     {
 10         static void Main(string[] args)
 11         {
 12             Chain chain = new Chain();
 13 
 14             Block block1 = new Block("轉賬10元");
 15             chain.AddNewBlock(block1);
 16             Block block2 = new Block("轉賬30元");
 17             chain.AddNewBlock(block2);
 18 
 19 
 20             //查看當前數據鏈總共數據快數
 21             chain.ViewBlockCount();
 22 
 23             //查看所有數據鏈
 24             chain.ViewAllBlocks();
 25 
 26             //驗證數據鏈
 27             Console.WriteLine(chain.Validate());
 28 
 29             //模擬篡改數據
 30             chain.Blocks[1].Prehash = "";
 31 
 32             //驗證數據鏈
 33             Console.WriteLine(chain.Validate());
 34         }
 35     }
 36 }
 37 
 38 //數據塊
 39 public class Block
 40 {
 41     //數據
 42     private string data;
 43     //前一個Block的hash
 44     private string prehash;
 45     //當前Block的hash
 46     private string curhash;
 47     public Block(string data)
 48     {
 49         this.prehash = "";
 50         this.data = data;
 51         this.curhash = "";
 52     }
 53 
 54     //注意:這里為了模擬篡改數據專門封裝的字段
 55     public string Data { get => data; set => data = value; }
 56     public string Prehash { get => prehash; set => prehash = value; }
 57     public string Curhash { get => curhash; set => curhash = value; }
 58 
 59     //計算當前Block的Hash
 60     public string ComputeHash(string prehash)
 61     {
 62         this.prehash = prehash;
 63         return SHA256(this.data + this.prehash);
 64     }
 65 
 66     //Hash256計算
 67     public string SHA256(string str)
 68     {
 69         //如果str有中文，不同Encoding的sha是不同的！！
 70         byte[] SHA256Data = Encoding.UTF8.GetBytes(str);
 71 
 72         SHA256Managed Sha256 = new SHA256Managed();
 73         byte[] by = Sha256.ComputeHash(SHA256Data);
 74 
 75         return BitConverter.ToString(by).Replace("-", "").ToLower();
 76     }
 77 
 78     //顯示Block數據
 79     public void ViewInfo()
 80     {
 81         Console.WriteLine("====");
 82         Console.WriteLine("[prehash]->" + this.prehash);
 83         Console.WriteLine("[data]->" + this.data);
 84         Console.WriteLine("[hash]->" + this.curhash);
 85     }
 86 }
 87 
 88 public class Chain
 89 {
 90     private List<Block> blocks;
 91 
 92     public List<Block> Blocks { get => blocks; set => blocks = value; }
 93 
 94     public Chain()
 95     {
 96         this.blocks = new List<Block>();
 97         Block genesisBloc = new Block("源數據塊");
 98         genesisBloc.Curhash = genesisBloc.ComputeHash("genesis");
 99         AddNewBlock(genesisBloc);
100     }
101 
102     public void ViewBlockCount()
103     {
104         Console.WriteLine("當前數據塊總數->" + this.blocks.Count);
105     }
106 
107     //添加Block
108     public void AddNewBlock(Block newblock)
109     {
110         //空鏈的情況
111         if (this.blocks.Count == 0)
112         {
113             this.blocks.Add(newblock);
114             newblock.Curhash = newblock.ComputeHash(newblock.Prehash);
115             return;
116         }
117         /*鏈接新Block*/
118         //新的Block的prehash是上一個block的curhash
119         newblock.Prehash = this.blocks[this.blocks.Count - 1].Curhash;
120         newblock.Curhash = newblock.ComputeHash(newblock.Prehash);
121         /*添加新Block*/
122         this.blocks.Add(newblock);
123     }
124 
125     //查看所有Block
126     public void ViewAllBlocks()
127     {
128         foreach (var item in this.blocks)
129         {
130             item.ViewInfo();
131         }
132     }
133 
134     //驗證Chain
135     public bool Validate()
136     {
137         //無任何數據塊的情況
138         if (this.blocks.Count == 0)
139         {
140             Console.WriteLine("[數據鏈異常]->數據鏈為空！");
141             return false;
142         }
143         //只有源數據塊的情況
144         else if (this.blocks.Count == 1)
145         {
146             Console.WriteLine("驗證完畢！");
147             return true;
148         }
149 
150         //遍歷校驗標志
151         bool checkBlockSign = true;
152 
153         //遍歷檢查數據塊，因為不檢查源數據塊，下標從1開始
154         for (int checkBlockIndex = 1; checkBlockIndex < this.blocks.Count; checkBlockIndex++)
155         {
156             //檢驗curhash
157             var checkBlock = this.blocks[checkBlockIndex];
158             if (checkBlock.Curhash != checkBlock.ComputeHash(checkBlock.Prehash))
159             {
160                 Console.WriteLine("[數據被篡改]->" + checkBlockIndex);
161                 checkBlockSign = false;
162                 break;
163             }
164             /*            //驗證prehash
165                         if (checkBlock.Prehash != this.blocks[checkBlockIndex - 1].Curhash)
166                         {
167                             Console.WriteLine("[數據鏈斷裂]->" + checkBlockIndex);
168                             checkBlockSign = false;
169                             break;
170                         }*/
171         }
172         Console.WriteLine("驗證完畢！");
173         return checkBlockSign;
174     }
175 }