C# 对称加密解密算法

可用于文件，和数据库字段的加解密。

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace Comon
{
  /// <summary>
  /// KeyCryp 的摘要说明。
  /// </summary>
  public class KeyCryp
  {
   private SymmetricAlgorithm mobjCryptoService;
   private string Key;

  /// <summary>
   /// 对称加密类的构造函数
   /// </summary>
   public KeyCryp()
   {
    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 = "E4ghj*Ghg7!rNIfb&95GUY86GfghUb#er57HBh(u%g6HJ($jhWk7&!hg4ui%$hjk";
    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();
   }
 
  }
}