Patent ID: 7263611
Filing Date: 2007-08-28
Classification: H04L

Abstract:
1. A method for content access control operative to enable authorized devices to access protected content and to prevent unauthorized devices from accessing protected content, the method comprising: providing a plurality of authorized devices, each of the plurality of authorized devices belonging to a plurality of groups and each of the devices being supplied with a plurality of group keys, each of said group keys supplied to a given one of the plurality of authorized devices corresponding to one of the plurality of groups to which the authorized device belongs, at least most of the plurality of authorized devices having a plurality of group keys which is at least partially different from the plurality of group keys of the remaining one of the plurality of authorized devices; and thereafter, when at least one of said plurality of authorized devices is to be denied access to said protected content, sending protected content to said plurality of authorized devices which content is encrypted in a manner such that all group keys supplied to said at least one of said plurality of authorized devices to be denied access to said protected content are unable to enable access to said protected content.