Reception apparatus for authenticated access to coded broadcast signals
AssigneeBritish Telecommunications public limited company
InventorJohn C Sager
Life of this patent
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Abstract
Decoding of a broadcast signal is enabled only if it carries an identifier verified by its presence (or absence) in a stored list. The list is loaded from a removable module. Preferably the loading of the list is conditional upon the success of a cryptographically authenticated exchange of signals between the module and the main part of the receiver.
Claims16
Apparatus for receiving broadcast transmissions, which transmissions contain identifiers identifying the origin of the transmission, the apparatus including:
- a store for storing data identifying transmissions which the apparatus is or is not permitted to receive;
- means for loading the store with such data;
- and
- means for comparing received identifiers with the contents of the store and to enable or disable reception in dependence on the result of the comparison;
- wherein the apparatus has a fixed part and a removable part;
- wherein the removable part contains a further store containing the said data;
- the loading means being operable to transfer the contents of the further store into the first-mentioned store;
- and
- wherein each of the fixed and removable parts has means storing a verification number (X) and the loading means is operable to perform the transfer only after a verification step indicating that the verification numbers tally.
A method for receiving broadcast transmissions, which transmissions contain identifiers identifying the origin of the transmission, the method including:
- storing data in a store identifying transmissions which the apparatus is or is not permitted to receive;
- loading the store with such data;
- and
- comparing received identifiers with the contents of the store and to enable or disable reception in dependence on the result of the comparison;
- wherein a removable and separable part contains a further store containing the said data;
- transferring the contents of the further store into the first-mentioned store;
- and
- wherein each of fixed and removable parts has stores a verification number (X) and the transfer is performed only after a verification step indicating that the verification numbers tally.
Dependencies are inferred from the claim text.