C# 使用DES加密，解密字符串

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace NoticeBoard
{
/// <summary>
/// DES加密解密算法
/// </summary>
public class DES
{
/// <summary>
/// DES加密算法
/// sKey为8位或16位
/// </summary>
/// <param name="pToEncrypt">需要加密的字符串</param>
/// <param name="sKey">密钥</param>
/// <returns></returns>
public string DesEncrypt(string pToEncrypt, string sKey)
{
StringBuilder ret = new StringBuilder();

try
{
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
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);
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();

foreach (byte b in ms.ToArray())
{
ret.AppendFormat("{0:X2}", b);
}
ret.ToString();
}
catch
{

}
return ret.ToString();
//return a;
}
/// <summary>
/// DES解密算法
/// sKey为8位或16位
/// </summary>
/// <param name="pToDecrypt">需要解密的字符串</param>
/// <param name="sKey">密钥</param>
/// <returns></returns>
public string DesDecrypt(string pToDecrypt, string sKey)
{
MemoryStream ms = new MemoryStream();

try
{
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
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;
}
des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);

CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
StringBuilder ret = new StringBuilder();

}
catch
{

}

return System.Text.Encoding.Default.GetString(ms.ToArray());
}
}

/// <summary>  
/// 对称加密解密算法类  
/// </summary>  
public class Rijndael
{
private SymmetricAlgorithm mobjCryptoService;
private string Key;
/// <summary>  
/// 对称加密类的构造函数  
/// </summary>  
public void SymmetricMethod()
{
mobjCryptoService = new RijndaelManaged();
Key = "Guz(%&hj7x89H$yuBI0456FtmaT5&fvHUFCy76*h%(HilJ$lhj!y6&(*jkP87jH7";
}
/// <summary>  
/// 获得密钥  
/// </summary>  
/// <returns>密钥</returns>  
private byte[] GetLegalKey()
{
string sTemp = Key;
mobjCryptoService.GenerateKey();
byte[] bytTemp = mobjCryptoService.Key;
int KeyLength = bytTemp.Length;
if (sTemp.Length > KeyLength)
sTemp = sTemp.Substring(0, KeyLength);
else if (sTemp.Length < KeyLength)
sTemp = sTemp.PadRight(KeyLength, ' ');
return ASCIIEncoding.ASCII.GetBytes(sTemp);
}
/// <summary>  
/// 获得初始向量IV  
/// </summary>  
/// <returns>初试向量IV</returns>  
private byte[] GetLegalIV()
{
string sTemp = "aclejaspwejgjdjfasrweojksdf$%#@!^!@&#*ajke^!@#jka";     //key 随便写。。
mobjCryptoService.GenerateIV();
byte[] bytTemp = mobjCryptoService.IV;
int IVLength = bytTemp.Length;
if (sTemp.Length > IVLength)
sTemp = sTemp.Substring(0, IVLength);
else if (sTemp.Length < IVLength)
sTemp = sTemp.PadRight(IVLength, ' ');
return ASCIIEncoding.ASCII.GetBytes(sTemp);
}
/// <summary>  
/// 加密方法  
/// </summary>  
/// <param name="Source">待加密的串</param>  
/// <returns>经过加密的串</returns>  
public string Encrypto(string Source)
{
byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source);
MemoryStream ms = new MemoryStream();
mobjCryptoService.Key = GetLegalKey();
mobjCryptoService.IV = GetLegalIV();
ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();
CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
cs.Write(bytIn, 0, bytIn.Length);
cs.FlushFinalBlock();
ms.Close();
byte[] bytOut = ms.ToArray();
return Convert.ToBase64String(bytOut);
}
/// <summary>  
/// 解密方法  
/// </summary>  
/// <param name="Source">待解密的串</param>  
/// <returns>经过解密的串</returns>  
public string Decrypto(string Source)
{
byte[] bytIn = Convert.FromBase64String(Source);
MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length);
mobjCryptoService.Key = GetLegalKey();
mobjCryptoService.IV = GetLegalIV();
ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();
CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
StreamReader sr = new StreamReader(cs);
return sr.ReadToEnd();
}
}

}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Windows.Forms;
using System.Xml;

namespace NoticeBoard
{
public class StaticClass
{

#region 加密解密

public static DES dd = new DES();

public static string StringKey = "A123456."; // 加密密钥

/// <summary>
/// 解密
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
public static string StringDecder(string str)
{
return dd.DesDecrypt(str, StringKey);
}

/// <summary>
/// 加密
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
public static string StringEncoder(string str)
{
return dd.DesEncrypt(str, StringKey);
}

#endregion

}
}