Patent ID: 8997252
Filing Date: 2015-03-31
Classification: G06F,H04L

Abstract:
1. A conditional access system (CAS) computer in a downloadable CAS, the CAS computer comprising: a data storage configured to store, for each of a plurality of client devices, a cryptographic identity and security information for determining whether a download manager certificate (DMC) for the client device is secure; and a hardware processor configured to: determine, using the DMC, security information including a DMC key size and an expiration time of a DMC subordinate certificate authority (sub-CA) certificate, for a client device of the plurality of client devices, from the data storage device, wherein the DMC key size is a key size of a DMC public key saved in the data storage; determine whether the DMC is valid based on the expiration time of the DMC sub-CA certificate and on the DMC key size; if the DMC is determined to be invalid, not provide the cryptographic identity for the client device to the client device; if the DMC is determined to be valid, send the cryptographic identity for the client device to the client device protected using the DMC and at a later time, if the DMC key size is considered to be still sufficiently secure, a validity of each DMC is extended by issuing a new DMC sub-CA certificate having extended lifetime with a same public key as the DMC sub-CA certificate; and determine at a later time whether the cryptographic identity of the client device is configured to be used based on the DMC public key size.