How is the message turned into choices?
Each letter is given a value between 1 and 26 and then the 5 bit binary representation is used to make the choices. For instance, the letter A is 00001 and the letter B is 00010. The word ‘BAD’ would be converted into a string ‘000010001000100’. These bits are used to make choices. If there are only two choices, then one bit is chewed up with each choice.