APPARATUS AND METHOD FOR CONTROLLING ACCESS TO BROADCAST SIGNALS

摘要

A method of controlling access to a broadcast signal characterised by the method comprising: issuing a first substantially unique key to each intending user; issuing to each user to be allowed access a message enciphered by use of the key unique to that user so as to permit local deciphering of the ciphered message by use of the issued first key to constitute a second key; and broadcasting a signal enciphered by use of said second key so as to permit local deciphering of the ciphered signal by use of the second key. The invention also provides a television receiver control apparatus for use with the above method.