On Golomb-Posner codes and a remark of W.W. Wu about secret-sharing systems

In a recent book (Elements of Digital Satellite Communication, vol.II, 1985), W.W. Wu has shown that all the secret-sharing systems known at the time his book was written can be described in terms of Reed-Solomon codes. He has also remarked that all are connected with latin squares and has illustrated this remark by means of examples. However, his examples construct secret-sharing systems in which the secret can be unlocked with only two keys. It is shown here that this is necessarily the case when latin squares are used. For this purpose. Wu´s observations are replaced by a theorem, one which also shows a connection with Golomb-Posner codes