When creating a keycard with a Kaba mag key writer with a PMS (Property Management System) or other software you need to calculate the LRC byte of the entire string. There are some examples from Kaba on how to do this, but not one for C# which would be the language that I needed to create this interface in.

Here is what I ended up doing:

private char GetKabaLRC(string s)
{
     char LRC = (char)(0);
     for (int i = 0; i < s.Length; i++)
     {
          LRC ^= s[i];
     }
     return LRC;
}