Patent ID: 7512238
Filing Date: 2009-03-31
Classification: H04L,H04N

Abstract:
1. A method for detecting loss of stream cipher synchronization between a transmitter and a receiver in a video processing system, the method comprising: transmitting an encrypted video frame from the transmitter to the receiver; receiving, at the transmitter, a re-encrypted pixel value from the receiver; obtaining, at the transmitter, a plaintext value for a selected pixel from an original video frame, wherein the original video frame corresponds to the encrypted video frame, and wherein the selected pixel corresponds to the re-encrypted pixel value received from the receiver; encrypting the plaintext value for the selected pixel into a new encrypted value; and detecting, at the transmitter, loss of stream cipher synchronization, based at least in part on (a) the re-encrypted pixel value received from the receiver and (b) the new encrypted value.