交换密钥与安全传输

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 using System.Security.Cryptography;
 7 using System.IO;
 8 
 9 namespace SecurityDemo
10 {
11     class Program
12     {
13         static CngKey aliceKey;
14         static CngKey bobKey;
15         static byte[] alicePubKeyBlob;
16         static byte[] bobPubKeyBlob;
17 
18         static void Main(string[] args)
19         {
20             Console.ForegroundColor = ConsoleColor.Green;
21             CreateKey();
22             byte[] encrytpedData = AliceSendData("123");
23             BobReceiveData(encrytpedData);
24             Console.ReadKey();
25         }
26 
27         public static void CreateKey()
28         {
29             aliceKey = CngKey.Create(CngAlgorithm.ECDiffieHellmanP256);
30             bobKey = CngKey.Create(CngAlgorithm.ECDiffieHellmanP256);
31             alicePubKeyBlob = aliceKey.Export(CngKeyBlobFormat.EccPublicBlob);
32             bobPubKeyBlob = bobKey.Export(CngKeyBlobFormat.EccPublicBlob);
33         }
34 
35         private static byte[] AliceSendData(string msg)
36         {
37             Console.WriteLine(string.Format("Alice Send Msg: {0}", msg));
38             byte[] rawdata = Encoding.UTF8.GetBytes(msg);
39             byte[] encryptedData = null;
40             using (var aliceAlgorithm = new ECDiffieHellmanCng(aliceKey))
41             using (CngKey bobPubKey = CngKey.Import(bobPubKeyBlob, CngKeyBlobFormat.EccPublicBlob))
42             {
43                 byte[] symmkey = aliceAlgorithm.DeriveKeyMaterial(bobPubKey);
44 
45                 Console.WriteLine(string.Format("Alice Create this symmtric key with {0}", Convert.ToBase64String(symmkey)));
46 
47                 var aes = new AesCryptoServiceProvider();
48                 aes.Key = symmkey;
49                 aes.GenerateIV();
50                 using (ICryptoTransform encryptor = aes.CreateEncryptor())
51                 using (MemoryStream ms = new MemoryStream())
52                 {
53                     var cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write);
54                     ms.Write(aes.IV, 0, aes.IV.Length);
55                     cs.Write(rawdata, 0, rawdata.Length);
56                     cs.Close();
57                     encryptedData = ms.ToArray();
58                 }
59                 aes.Clear();
60             }
61 
62             Console.WriteLine(Convert.ToBase64String(encryptedData));
63             return encryptedData;
64         }
65 
66         private static void BobReceiveData(byte[] encryptData)
67         {
68             byte[] rawdata = null;
69             var aes = new AesCryptoServiceProvider();
70             int nBytes = aes.BlockSize >> 3; // bit to Byte, need to devide 8
71             byte[] iv = new byte[nBytes];
72 
73             for (int i = 0; i < iv.Length; i++)
74                 iv[i] = encryptData[i];
75             using (var bobAlgorithm = new ECDiffieHellmanCng(bobKey))
76             using (CngKey alicePubKey = CngKey.Import(alicePubKeyBlob, CngKeyBlobFormat.EccPublicBlob))
77             {
78                 byte[] symmKey = bobAlgorithm.DeriveKeyMaterial(alicePubKey);
79                 Console.WriteLine(Convert.ToBase64String(symmKey));
80                 aes.Key = symmKey;
81                 aes.IV = iv;
82             }
83             using (ICryptoTransform decryptor = aes.CreateDecryptor())
84             using (MemoryStream ms = new MemoryStream())
85             {
86                 var cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Write);
87                 cs.Write(encryptData, nBytes, encryptData.Length - nBytes);
88                 cs.Close();
89                 rawdata = ms.ToArray();
90                 Console.WriteLine(Encoding.UTF8.GetString(rawdata));
91             }
92             aes.Clear();
93         }
94     }
95 
96 }