Security processor and methods for registering access entitlements and cryptographic keys

摘要

This security method for scrambled multimedia signal decoder comprises at least one rewritable lock (62, 64), the value of which can be toggled at least between a first and a second value in response to an EMM message, and in which a registration module is able, in response to one and the same EMM registration message for writing new access entitlements or new cryptographic keys, to authorize and, alternatively, to prohibit this registration depending on the value of the lock.

主权项

1. A security processor for a decoder of multimedia signals scrambled using a control word and which is configurable to have an operating mode as either a disposable or standard security processor, the processor comprising:
a decoder capable of decoding the control word present in an ECM message (Entitlement Control Message) to allow the scrambled multimedia signals to be unscrambled, a rewritable non-volatile memory containing access entitlements, a comparator capable of comparing the access conditions present in the ECM message received with the access entitlements placed in the rewritable non-volatile memory and to prevent unscrambling of the multimedia signals if the access entitlements do not correspond to the access conditions received and to authorize unscrambling of the scrambled multimedia signals if the access entitlements in the rewritable non-volatile memory correspond to the access conditions received, a register for the registration of new access entitlements in the rewritable non-volatile memory in response to the receipt of an EMM message (Entitlement Management Message) for the registration of new access entitlements, and at least one rewritable lock whose value can be toggled between at least a first and a second value in response to an EMM message, and wherein the register is able to authorise and alternatively prohibit this registration of new access entitlements, depending upon the value of the rewritable lock, and in response to a given EMM message for the registration of new access entitlements, configuring an operating mode of the security processor as one of: a disposable security processor or a standard security processor.