The use of coding has become particularly significant in recent years. One way to encrypt or code a message uses matrices and their properties. We start with a message coded into matrix form, called A. Multiply A by another matrix B to get AB and send the message.
a) What would we need to decode the message at the other end to get our original matrix A?
b) Would there be any restrictions on this practice?
Matrices and Their Use in Coding and Encription is discussed.