Patent ID: 7805607

Claim:
A method for verifying that data received by a receiver apparatus have been sent by a transmitter authorized by a trusted third party to transmit the data, the transmitter and the receiver apparatus being connected to a digital network, the method performed by the receiver apparatus comprising: (a) receiving, at the receiver apparatus, the data and an identifier for the data; (b) generating a random number; (c) broadcasting said random number and said identifier over the network; (d) receiving from the transmitter a response computed by applying a first function to said random number and to said identifier; (e) verifying the received response by applying a second function to the received response, to said random number and to said identifier; the first function having previously been delivered to the transmitter by the trusted third party and the second function being a function for verifying the result of the first function, previously delivered by the trusted third party to the receiver apparatus; wherein the receiver apparatus does not know the identity of the transmitter; and wherein the transmitter is a set top box and the receiver apparatus is a digital television.