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:
Sep. 14, 2010
Filed:
Apr. 26, 2005
Takashi Murakami, Kyoto, JP;
Yasuyuki Shintani, Hyogo, JP;
Takashi Murakami, Kyoto, JP;
Yasuyuki Shintani, Hyogo, JP;
Panasonic Corporation, Osaka, JP;
Abstract
When a common key is updated to a new common key, it is possible to prevent the generation of a period during which not all the general communication apparatuses are enabled to make mutual communications using encrypted data while at the same time reducing the memory consumption of the general communication apparatus. A common key control apparatustransmits a first status transition request Rto all the general communication apparatuses when all the general communication apparatusesmade a transition to a distribution completed status, and transmits a second status transition request Rto all the general communication apparatuses when all the general communication apparatusesmade a transition to an in-transit status. The general communication apparatusmakes a transition from the update completed status to the distribution completed status upon receipt of a new common key from the common key control apparatus, while it makes a transition from the distribution completed status to the in-transit status upon receipt of the first status transition request and it restores the state to the update completed status from the in-transit status upon receipt of the second status transition request.