Patent ID: 6650753
Filing Date: 2003-11-18
Classification: G11B,H04L,H04N

Abstract:
A decryption module for a digital video device configured for receiving and presenting at least one digital program, comprising:computer readable code means for receiving a session key block representable be a matrix having at least dimensions â€œiâ€  and â€œjâ€ , the session key block including encrypted session numbers xi, i=1 to N, each session key number xi being encrypted by â€œjâ€  device keys Sj,i, j=1 to M, â€œNâ€  being the number of device keys in each of M sets of keys; computer readable code means for accessing plural local device keys, the device being assigned one and only one local device key for each variable â€œiâ€ ; and computer readable code means for decrypting a session key from the session key block using the local device keys.