//名稱空間 <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
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象
StringBuilder ret = new StringBuilder();
return System.Text.Encoding.Default.GetString(ms.ToArray());
}
//-------代碼完畢--------------------
注意：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。
本人使用Windows2000 Server .Net Framework SP3 ，VS.Net下在asp.net下使用成功，加密解密正常！