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:
Jan. 05, 2010
Filed:
Feb. 04, 2004
Applicants:
Yoshimichi Kudo, Fujisawa, JP;
Manabu Sasamoto, Yokohama, JP;
Hiroo Okamoto, Yokohama, JP;
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04L 29/06 (2006.01);
U.S. Cl.
CPC ...
Abstract
Before content transmission, the content transmitting device and the content receiving device mutually authenticate each other to verify that the other device respects copyright and rightfully handles content, and then content is encrypted by shared key data and transmitted. It is arranged that in an authentication process, a time from transmission of an authentication request or a time from transmission of an authentication response until arrival of receipt acknowledgement data is measured and only when a measured time is less than a fixed upper-limit value, content is transmitted.