/// 

      /// Input a KID number, and the return value is a mathematical
      /// Mod 10 value of this KID.
      /// 
      /// KID to be evaluated
      /// The Mod 10 Digit
      /// 
      /// KID: 0000001075000102004
      /// Check Digit: 7
      /// Math:
      ///  0 0 0 0 0 0 1 0 7 5 0 0 0 1 0 2 0 0 4
      ///  2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2
      /// +0+0+0+0+0+0+2+0+5+5+0+0+0+1+0+2+0+0+8 = 23

      /// The digits in the two lines are Multiplicated

      /// ex: 7*2 = 14 = 1+4 = 5
      /// ex: 1*2 = 2
      /// If Sum Exeeds 9 digits are added ex: 14 = 1+4 = 5
      /// Take 10 - last digit = 10-3=7
      /// CheckDigit is then 7
      ///
      public int GenerateLuhn(string sInput)
      {
         int length = sInput.Length;
         int iLuhnKey;
         int sum = 0;
         int offset = length-1 % 2;
         byte[] digits = new System.Text.ASCIIEncoding().GetBytes(sInput);
            
         for (int i = 0; i < length; i++)
         {
            digits[i] -= 48;
            if (((i + offset) % 2) == 0)
               digits[i] *= 2;
        
            sum += (digits[i] > 9) ? digits[i] - 9 : digits[i];
         }
         int iModulo = sum%10;
         if(iModulo > 0)
            iLuhnKey = 10 - iModulo;
         else
            iLuhnKey = 0;
         return iLuhnKey;
      }