发一个加密的方法

//声明加密字符生成的随机数的位数
  public const int LENGTH = 32;
  //声明加密字符前后的分隔长度
  public const int LEN = 4;

///方法作用:根据参数对其加密
  ///参数:
  ///  string strEncrypt;欲加密的字符
  ///返回结果:加密后的字符
  public static byte[] SourceEncrypt(string strEncrypt)
  {
   string source = Encrypt(strEncrypt);
   //first
   string first = Encrypt(source.Substring(0,LEN));
   //second
   string second = Encrypt(source.Substring(LEN-1,source.Length-LEN));
   //third
   string third = Encrypt(source.Substring(source.Length-LEN,LEN));
   //four
   byte[] Random = new byte[LENGTH];
   RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
   rng.GetNonZeroBytes(Random);
   string four = Encrypt(System.Text.Encoding.ASCII.GetString(Random));
   string all = first+second+third+four;
   return System.Text.Encoding.ASCII.GetBytes(all);
  } // end SourceEncrypt

  ///方法作用:对参数进行加密
  ///参数: 
  ///  string strEncrypt:欲加密的字符
  /// 返回结果:加密后的字符
  public static string Encrypt(string strEncrypt)
  {
   SHA256Managed sha = new SHA256Managed();
   byte[] VALUE = sha.ComputeHash(System.Text.Encoding.ASCII.GetBytes(strEncrypt));   
   return System.Text.Encoding.ASCII.GetString(VALUE);
  } // end Encrypt

  ///方法作用:对参数进行比较
  ///参数:
  ///  string strSource:原字符
  ///  string strObject:目标字符
  /// 返回结果:bool是否相等
  public static bool CompareEncrypt(byte[] strSource,string strobject)
  {
   bool result = true;
   byte[] strObject = SourceEncrypt(strobject);
   //strObject = SourceEncrypt(strObject);
   if((strSource==null) || (strObject==null) || (strSource.Length != strObject.Length))
    result = false;
   else
   {
    //strSource = strSource.Substring(0,strSource.Length-LENGTH);
    //strObject = strObject.Substring(0,strObject.Length-LENGTH);
    //byte[] Source = System.Text.Encoding.ASCII.GetBytes(strSource);
    //byte[] Obj   = System.Text.Encoding.ASCII.GetBytes(strObject);
    byte[] Source = strSource;
    byte[] Obj = strObject;
    if(Source.Length != Obj.Length)
     result = false;
    else
    {
     for(int i = 0; i < Source.Length-LENGTH; i++)
     {
      if(Source[i] != Obj[i])
      {
       result = false;
       break;
      }
     }
    }
   }

   return result;
  } //end CompareyEncrypt

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