公开(公告)号：US11943491B2

公开(公告)日：2024-03-26

申请号：US18306085

申请日：2023-04-24

申请人： NAGRAVISION Sarl

发明人： Christian Schwarz ,  Andre Nicoulin ,  Didier Hunacek

IPC分类号： H04N21/2347 ,  G06F21/57 ,  H04L9/16 ,  H04L9/32 ,  H04N7/167 ,  H04N21/266 ,  H04N21/418 ,  H04N21/4405 ,  H04N21/4623

CPC分类号： H04N21/2347 ,  G06F21/57 ,  H04L9/16 ,  H04L9/3213 ,  H04N7/167 ,  H04N21/26606 ,  H04N21/26613 ,  H04N21/4181 ,  H04N21/4405 ,  H04N21/4623

摘要： Devices, servers, systems and methods for content protection are provided. Disclosed embodiments improve temporal granularity of controlling access to the protected content and increase resilience against attacks attempting to prevent re-evaluation of conditions of access. Enforcement of re-evaluation may be based on the receipt and/or verification of tokens. In some embodiments, re-evaluation is enforced by periodically rendering content keys required for content decryption unuseable and/or clearing content keys already in use.