使用DES加密解密代碼（C# & vb.Net）

引用
C#
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//名稱空間  
using  System;  
using  System.Security.Cryptography;  
using  System.IO;  
using  System.Text;  

//方法  
//加密方法  
public    string  Encrypt(string  pToEncrypt,  string  sKey)  
{  
           DESCryptoServiceProvider  des  =  new  DESCryptoServiceProvider();  
           //把字符串放到byte數組中  
                 //原來使用的UTF8編碼，我改成Unicode編碼了，不行  
           byte[]  inputByteArray  =  Encoding.Default.GetBytes(pToEncrypt);  
           //byte[]  inputByteArray=Encoding.Unicode.GetBytes(pToEncrypt);  

           //建立加密對象的密鑰和偏移量  
           //原文使用ASCIIEncoding.ASCII方法的GetBytes方法  
           //使得輸入密碼必須輸入英文文本  
           des.Key  =  ASCIIEncoding.ASCII.GetBytes(sKey);  
           des.IV  =  ASCIIEncoding.ASCII.GetBytes(sKey);  
           MemoryStream  ms  =  new  MemoryStream();  
           CryptoStream  cs  =  new  CryptoStream(ms,  des.CreateEncryptor(),CryptoStreamMode.Write);  
           //Write  the  byte  array  into  the  crypto  stream  
           //(It  will  end  up  in  the  memory  stream)  
           cs.Write(inputByteArray,  0,  inputByteArray.Length);  
           cs.FlushFinalBlock();  
           //Get  the  data  back  from  the  memory  stream,  and  into  a  string  
           StringBuilder  ret  =  new  StringBuilder();  
           foreach(byte  b  in  ms.ToArray())  
                       {  
                       //Format  as  hex  
                       ret.AppendFormat("{0:X2}",  b);  
                       }  
           ret.ToString();  
           return  ret.ToString();  
}  

//解密方法  
public    string  Decrypt(string  pToDecrypt,  string  sKey)  
{  
           DESCryptoServiceProvider  des  =  new  DESCryptoServiceProvider();  

           //Put  the  input  string  into  the  byte  array  
           byte[]  inputByteArray  =  new  byte[pToDecrypt.Length  /  2];  
           for(int  x  =  0;  x  <  pToDecrypt.Length  /  2;  x++)  
           {  
                     int  i  =  (Convert.ToInt32(pToDecrypt.Substring(x  *  2,  2),  16));  
               inputByteArray[x]  =  (byte)i;  
           }  

           //建立加密對象的密鑰和偏移量，此值重要，不能修改  
           des.Key  =  ASCIIEncoding.ASCII.GetBytes(sKey);  
           des.IV  =  ASCIIEncoding.ASCII.GetBytes(sKey);  
           MemoryStream  ms  =  new  MemoryStream();  
           CryptoStream  cs  =  new  CryptoStream(ms,  des.CreateDecryptor(),CryptoStreamMode.Write);  
           //Flush  the  data  through  the  crypto  stream  into  the  memory  stream  
           cs.Write(inputByteArray,  0,  inputByteArray.Length);  
           cs.FlushFinalBlock();  

           //Get  the  decrypted  data  back  from  the  memory  stream  
           //建立StringBuild對象，CreateDecrypt使用的是流對象，必須把解密後的文本變成流對像  
           StringBuilder  ret  =  new  StringBuilder();  
             
           return  System.Text.Encoding.Default.GetString(ms.ToArray());  
}  
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vb.Net :
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Imports System.Web.Security
Imports System.Security
Imports System.Security.Cryptography
Imports System.Text

Public Shared Function Encrypt(ByVal pToEncrypt As String, ByVal sKey As String) As String
     Dim des As New DESCryptoServiceProvider()
     Dim inputByteArray() As Byte
     inputByteArray = Encoding.Default.GetBytes(pToEncrypt)
     '建立加密對象的密鑰和偏移量
     '原文使用ASCIIEncoding.ASCII方法的GetBytes方法
     '使得輸入密碼必須輸入英文文本
     des.Key = ASCIIEncoding.ASCII.GetBytes(sKey)
     des.IV = ASCIIEncoding.ASCII.GetBytes(sKey)
     '寫二進制數組到加密流
     '(把內存流中的內容全部寫入)
     Dim ms As New System.IO.MemoryStream()
     Dim cs As New CryptoStream(ms, des.CreateEncryptor, CryptoStreamMode.Write)
     '寫二進制數組到加密流
     '(把內存流中的內容全部寫入)
     cs.Write(inputByteArray, 0, inputByteArray.Length)
     cs.FlushFinalBlock()

     '建立輸出字符串     
     Dim ret As New StringBuilder()
     Dim b As Byte
     For Each b In ms.ToArray()
         ret.AppendFormat("{0:X2}", b)
     Next

     Return ret.ToString()
End Function

        '解密方法
Public Shared Function Decrypt(ByVal pToDecrypt As String, ByVal sKey As String) As String
     Dim des As New DESCryptoServiceProvider()
     '把字符串放入byte數組
     Dim len As Integer
     len = pToDecrypt.Length / 2 - 1
     Dim inputByteArray(len) As Byte
     Dim x, i As Integer
     For x = 0 To len
         i = Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16)
         inputByteArray(x) = CType(i, Byte)
     Next
     '建立加密對象的密鑰和偏移量，此值重要，不能修改
     des.Key = ASCIIEncoding.ASCII.GetBytes(sKey)
     des.IV = ASCIIEncoding.ASCII.GetBytes(sKey)
     Dim ms As New System.IO.MemoryStream()
     Dim cs As New CryptoStream(ms, des.CreateDecryptor, CryptoStreamMode.Write)
     cs.Write(inputByteArray, 0, inputByteArray.Length)
     cs.FlushFinalBlock()
     Return Encoding.Default.GetString(ms.ToArray)

End Function
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備註：
1. sKey輸入密碼的時候，必須使用英文字符，區分大小寫，且字符數量是8個，不能多也不能少，否則出錯。
2. asp.net1.1,vs.net2003,windows2003 server環境下C#和vb.net分別調試成功！