The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 24, 2001
Filed:
Jul. 07, 1998
Seiichi Domyo, Fujisawa, JP;
Hiroyoshi Tsuchiya, Yokohama, JP;
Seiko Kanno, Yokohama, JP;
Hiroyuki Ando, Kawasaki, JP;
Ichirou Morita, Kawasaki, JP;
Yasutsugu Kuroda, Kawasaki, JP;
Naoya Torii, Kawasaki, JP;
Hiroshi Miyauchi, Tokyo, JP;
Kazue Sako, Tokyo, JP;
Masashi Yamazaki, Tokyo, JP;
Other;
Abstract
The present invention has an object to overcome problems of a key recovery system using a conventional KRF system and to achieve efficient operation of the overall key recovery system. A key recovery system of the present invention includes check units,for checking whether a user has a recovery authorization for a common key KS, on the basis of a recovery condition RC specified by a recovery condition index RCI which is added to an encrypted message (encrypted message obtained by encrypting the common key KS with a public key KRCpub) supplied from a terminal (,to,) of the user concerned, and a key recovery control unit,which is provided separately from the check units,and decrypts the encrypted message with a private key KRCpri paired with the public key KRCpub to recover the common key. The check unit,supplies the common key KS recovered in the key recovery control unit,to the user concerned only when the user has the recovery authorization.