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:
May. 26, 2009
Filed:
Apr. 28, 2003
Yuji Watanabe, Yokohama, JP;
Masayuki Numao, Kawasaki, JP;
Yuji Watanabe, Yokohama, JP;
Masayuki Numao, Kawasaki, JP;
International Business Machines Corporation, Armonk, NY (US);
Abstract
Provided is a method for updating a group key in a highly secure manner and at high speed. A method includes: a step of making subscriber terminals () perform a part of decryption of an encrypted group key used to decrypt the information before distribution of the group key; a step of distributing the group key and individual decryption information used to perform a part of remaining decryption other than the part of decryption of the group key and corresponding to terminal devices to the subscriber terminals (); and a step of making the subscriber terminals () perform decryption of the group key using the decryption information being distributed and results obtained by implementing a part of decryption of the group key, the part of decryption previously being performed.