Apparatus and method for securing communication systems

A hacking prevention system for use with a network including a transmitter and a multiplicity of receivers, each receiver being independently enabled by a secret number and when enabled being responsive to data received from the transmitter for decrypting encrypted information, each of the multiplicity of receivers including: a first key generator, employing at least part of the data and a function which differs for at least a plurality of ones of the multiplicity of receivers, for generating a first key which is different for each receiver having a different function, a second key generator employing at least part of the data and the function to produce a second key, and a secret number generator utilizing the first key with the second key to produce the secret number which is the same for all of the multiplicity of receivers, whereby first and second keys intercepted at a first receiver cannot be effective to enable a second receiver having a different function.