Patent ID: 7548619

Claim:
In a copy protection system including a receiver interconnected to a descrambler module via a link, a method of copy protecting signals flowing from the descrambler module to the receiver via a link, comprising the steps of: (a) receiving a digital signal in the receiver, said digital signal including a scrambled signal; (b) generating a copy protection data signal at the receiver by utilizing a scheme which uses random number generation; (c) transmitting said digital signal from the receiver to the descrambler module via the link; (d) descrambling said scrambled signal in the descrambler module to obtain a descrambled signal; (e) converting said descrambled signal in the descrambler module into a copy protected signal using the copy protection data signal; (f) transmitting said copy protected signal from the descrambler to the receiver via the link; and (g) reconverting said copy protected signal to the descrambled signal by a function module in the receiver using said copy protection data signal, wherein use of the digital signal is prevented without access to the copy protection data signal, and wherein the copy protected signal can still be copied even without the copy protection data, but that copy cannot be used without the copy protection data signal.