US 11,671,637 B2
Content protection
Christian Schwarz, Vuarrens (CH); Andre Nicoulin, Lausanne (CH); and Didier Hunacek, Blonay (CH)
Assigned to NAGRAVISION S.A., Cheseaux-sur-Lausanne (CH)
Filed by NAGRAVISION S.A., Cheseaux-sur-Lausanne (CH)
Filed on Jan. 12, 2021, as Appl. No. 17/147,349.
Application 17/147,349 is a division of application No. 16/075,102, granted, now 10,931,983, previously published as PCT/EP2016/065129, filed on Jun. 29, 2016.
Claims priority of application No. 15174332 (EP), filed on Jun. 29, 2015.
Prior Publication US 2021/0168413 A1, Jun. 3, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 21/2347 (2011.01); H04N 21/266 (2011.01); H04N 21/418 (2011.01); H04N 21/4405 (2011.01); H04N 21/4623 (2011.01); G06F 21/57 (2013.01); H04L 9/16 (2006.01); H04L 9/32 (2006.01); H04N 7/167 (2011.01)
CPC H04N 21/2347 (2013.01) [G06F 21/57 (2013.01); H04L 9/16 (2013.01); H04L 9/3213 (2013.01); H04N 7/167 (2013.01); H04N 21/26606 (2013.01); H04N 21/26613 (2013.01); H04N 21/4181 (2013.01); H04N 21/4405 (2013.01); H04N 21/4623 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for decrypting encrypted media content, the method comprising:
receiving and storing an encrypted content key for decrypting encrypted media content;
evaluating an access condition and, if the access condition is met, decrypting the content key and enabling a descrambler to use the content key to decrypt the encrypted media content;
receiving the encrypted media content and decrypting the encrypted media content using the content key;
re-evaluating within an interval whether use of the content key should remain enabled; and,
if the re-evaluation is negative, preventing the descrambler from using the content key after the interval has passed in response to the re-evaluation even though the content key remains valid.