Key selection vector, mobile device and method for processing the key selection vector, digital content output device, and revocation list

A mobile device adapted to process a key selection vector for a revocation list, comprising:

• a controller to control processing of key selection vectors in the mobile device, the controller being configured to selectively process as a group, based on a received key selection vector for a revocation list, a plurality of key selection vectors storing the same or similar group property information in the at least one bit field;
• and
• a memory to store key selection vectors;
• wherein:
• the received key selection vector is structured to contain at least one bit field with a predetermined number of bits and at a predetermined location in the received key selection vector,
• the bit field contains a first predetermined bit pattern relating to a group property of a device, which group property allows to process as a group a plurality of key selection vectors storing the same or similar group property information in said at least one bit field, said plurality of key selection vectors being associated with a plurality of different devices, and
• the key selection vector for the revocation list contains at least another bit field containing a second predetermined bit pattern which indicates that the key selection vector identifies said plurality of key selection vectors which are associated with a plurality of different devices,
• a receiving section to receive the revocation list containing the at least one key selection vector;
• wherein the controller is adapted to determine whether said received at least one key selection vector of said revocation list is stored in the memory and to discard all data of said revocation list except said at least one key selection vector if it is not stored in said memory.

A method for processing a key selection vector for a revocation list by a mobile device including a processor, the method comprising the steps of:

• receiving a revocation list containing at least one key selection vector, the at least one key selection vector structured to contain at least one bit field with a predetermined number of bits and at a predetermined location in the key selection vector;
• wherein the bit field contains a first predetermined bit pattern relating to a group property of a device, which group property allows to process as a group a plurality of key selection vectors storing the same or similar group property information in said at least one bit field, said plurality of key selection vectors being associated with a plurality of different devices;
• and
• wherein the key selection vector for the revocation list contains at least another bit field containing a second predetermined bit pattern which indicates that the key selection vector identifies said plurality of key selection vectors which are associated with a plurality of different devices;
• and
• selectively processing as a group, based on the key selection vector in the revocation list, the plurality of key selection vectors storing the same or similar group property information in the at least one bit field using the processor;
• determining whether said received at least one key selection vector of said revocation list is stored in a memory;
• and
• discarding all data of said revocation list except said at least one key selection vector if it is not stored in said memory.