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:
Nov. 02, 2004
Filed:
Aug. 24, 2000
Matsushita Communication Industrial Co., Ltd., Yokohama, JP;
Abstract
In a set-up phase, the base station formulates the secret key S and holds it in secret. The secret information Si which are obtained by dividing the secret key S are distributed in secret to respective terminals to by using cryptographic communication means. In a preparatory phase, the base station broadcasts the preparatory information C (=g modp), the exclusive information C (=y5 modp), the ciphertext C (=M×K modp), and the particular terminal number to all terminals. In a key sharing phase, the terminal calculates a product of C {circumflex over ( )}(&lgr;(1, &Lgr;) modq) modp and C {circumflex over ( )}(&lgr;(5, &Lgr;) modq) modp by using the preparatory information C and the exclusive information C to obtain K and then calculates M, which are common data to the base station , by dividing the ciphertext C by K. The terminals to execute similar calculations. As a result, the terminals to can share mutually the common data M.