Patent ID: 7962964
Filing Date: 2011-06-14
Classification: G06F,H04N

Abstract:
1. A client device for use in a system having a server, the client device comprising: a receiving device configured to receive information material from the server, the information material containing a reversible modification providing a visually perceptible watermark having been applied to the information material by using an invertible algorithm which uses values generated from one or more keys, and to receive identifying information that distinguishes the information material from other information material available from the server and receive condition information which defines a predetermined condition that should be satisfied in order for the visually perceptible watermark to be removed; a transmission device which, in response to a user input providing enabling data which satisfies the predetermined condition, is configured to transmit the identifying information and the enabling data to the server, wherein in response to the transmission of the enabling data and the identifying information, the receiving device is further configured to receive the one or more keys and removal data defining the invertible algorithm for removing the visually perceptible watermark, the removal data being useable by a removal device to remove the visually perceptible watermark; and a storage device configured to store the information material that has had the visually perceptible watermark removed.