工作小结（十五）-MD5加密和解密

以下是加密和解密的代码：
using System.Text;
using System.Security.Cryptography;
using System.IO;

 1//MD5加密
 2    public static string Encode(string data)
 3    { 
 4        byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes("VavicApp");
 5        byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes("VavicApp");
 6        DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
 7        int i = cryptoProvider.KeySize;
 8        MemoryStream ms = new MemoryStream();
 9        CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);
10
11        StreamWriter sw = new StreamWriter(cst);
12        sw.Write(data);
13        sw.Flush();
14        cst.FlushFinalBlock();
15        sw.Flush();
16        return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
17
18    }
19    //MD5解密
20    public string Decode(string data)
21    {
22        string st = "VavicApp";
23        byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(st);
24        byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(st);
25
26        byte[] byEnc;
27        try
28        {
29            byEnc = Convert.FromBase64String(data);
30        }
31        catch
32        {
33            return null;
34        }
35
36        DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
37        MemoryStream ms = new MemoryStream(byEnc);
38        CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);
39        StreamReader sr = new StreamReader(cst);
40        return sr.ReadToEnd();
41    }
42