SYSTEM FOR SOFTWARE HAVING OPEN PART AND SECRET PART PROVIDED FOR PLURAL USERS

摘要

PURPOSE:To prevent the unauthorized use and to permit an open part not only to be changed and newly generated by a user but also to be shared among users by decoding a secret part of software detected by an encryption detecting circuit. CONSTITUTION:An encryption detecting circuit 14 of a memory controller 11 Which controls addressing and access for reference or the like to a memory 10 checks contents of supply software 8 and not only loads the open part, namely, non-ciphered part to a reference permission area 10a of the memory 10 as it is but also sends the ciphered part of supply software 8 to a data decoding circuit 15. The data decoding circuit 15 to which the ciphered part of supply software 8 is inputted reads in authentication information from an authentication information storage device 5 and generates a decoding key from this authentication information based on a prescribed decoding algorithm and decodes ciphered programs and data by the decoding key to load them to a reference inhibition area 10b of the memory 10.