Patent ID: 8151331

Claim:
A design information providing system comprising: a terminal apparatus used by a user manufacturing a product; a first design information providing server and a second design information providing server; and a patent license issuing server which concludes a license contract with said terminal apparatus regarding a patent necessary for manufacturing the product, wherein said design information providing system connects said terminal apparatus, said first and second design information providing servers and said patent license issuing server, so as to allow mutual communication therebetween, wherein said first design information providing server transmits, to said terminal apparatus, first design information indicating a specification necessary for manufacturing the product, wherein said patent license issuing server includes: a generating unit operable to generate a contractors list indicating a list of users of terminal apparatuses, each of the users indicated by the contractors list having concluded a license contract for a patent regarding the first design information; and an output unit operable to output the contractors list generated by said generating unit, and wherein said second design information providing server includes: a communication unit operable to receive, from said terminal apparatus, a request for an issuance of an encryption key which is second design information that is (i) necessary for manufacturing the product and (ii) unique to the product; an issuing unit operable to issue the encryption key to said terminal apparatus that has requested the issuance of the encryption key; an obtaining unit operable to obtain the contractors list outputted by said output unit; a database for storing the contractors list obtained by said obtaining unit; and a control unit operable to (i) browse the contractors list stored in said database and judge whether or not the contractors list includes a user of said terminal apparatus that has requested the issuance of the encryption key, when said communication unit receives the request for the issuance of the encryption key, and (ii) control said issuing unit to stop the issuance of the encryption key to said terminal apparatus, when said control unit judges that the contractors list does not include the user of said terminal apparatus that has requested the issuance of the encryption key.