Patent ID: 6898706

Claim:
In a networked client-server environment, apparatus for use in conjunction with a digital rights management system, the apparatus comprising: a client computer connected to the network, the client computer having: a processor; a memory having computer executable instructions stored therein; and an enforcer, contained within the digital rights management system, for controlling use of watermarked software objects, wherein the enforcer stores a predefined watermark key which defines a specific one of a plurality of identical watermarks embedded in the watermarked software object with different watermark keys to be used by the enforcer in subsequently controlling use of each one of said watermarked software objects, and wherein the predefined watermark key expires after a predefined period of time elapses since said predefined watermark key was initially stored in the enforcer; wherein the processor, in response to the stored executable instructions: establishes a network connection to a watermark key; issues a request to the server for a new watermark key; and utilizes either the predefined watermark key or the new watermark key, as received from the server, for the predefined watermark key for subsequent use in controlling access to the watermarked software objects until such time as the predefined key has expired after which the new watermark key is used instead; and the server, connected to the network, which, in response to the request: selects, if the predefined watermark key has not been revoked for the client computer, another one of predefined plurality of predetermined watermark keys for use in controlling access to the software watermarks objects as the new watermark key; sends the new watermark key to the client computer; and if the predefined watermark key has been revoked, does not supply the new watermark key to the client computer.