DECRYPTION PROCESSING APPARATUS, DECRYPTION PROCESSING METHOD, AND RECEIVER EMPLOYING THEM

摘要

PROBLEM TO BE SOLVED: To provide a decryption processing apparatus for suppressing increase in the power consumption and also suppressing increase in the circuit scale. SOLUTION: The decryption processing apparatus includes: a key schedule means 91 for generating a work key; a work key storage section 102 for storing only a work key corresponding to a particular packet ID; a work key selection section 103 for selecting the work key from a generated work key and a stored work key; a descrambler 900 for using the selected work key to carry out decryption; a PID comparison section 121 for discriminating whether an extracted packet ID is the particular packet ID; an update detection section 120 for detecting an updated work key; and a work key control section 123 for controlling production of the work key, storage of the work key and selection of the work key on the basis of a result of the PID comparison section 121 and a result of the update detection section 120. COPYRIGHT: (C)2005,JPO&NCIPI