US 12,445,421 B2
Apparatus, methods, and systems for pre-authentication, keep-authentication, and regain-authentication
Sergey V. Yarygin, San Jose, CA (US); Gyudong Kim, San Jose, CA (US); and Chandlee Harrell, Los Altos, CA (US)
Assigned to Analog Devices, Inc., Wilmington, MA (US)
Filed by Analog Devices, Inc., Wilmington, MA (US)
Filed on Dec. 8, 2021, as Appl. No. 17/545,702.
Prior Publication US 2023/0179584 A1, Jun. 8, 2023
Int. Cl. H04L 9/40 (2022.01); H04L 9/06 (2006.01); H04L 9/32 (2006.01); H04N 21/426 (2011.01)
CPC H04L 63/08 (2013.01) [H04L 9/0637 (2013.01); H04L 9/32 (2013.01); H04L 63/0428 (2013.01); H04L 63/0464 (2013.01); H04N 21/42623 (2013.01); H04L 2209/122 (2013.01); H04L 2209/34 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for maintaining authentication or reestablishing authentication on an encrypted stream, the method comprising:
identifying if an inputCtr signal is correct in a High-bandwidth Digital Content Protection (HDCP) environment, with the inputCtr signal defining a 64-bit counter indicative of a number of encrypted frames since start of HDCP encryption;
checking a section of the encrypted stream;
performing a packet integrity check on a data island packet;
performing a packet content check on the data island packet;
searching for a correct inputCtr; and
resynchronizing to the encrypted stream by applying the correct inputCtr without forcing an HDCP reauthentication when HDCP authentication failure is detected.