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. 12, 2013
Filed:
Jun. 30, 2009
Tatsuya Tomaru, Hatoyama, JP;
Tatsuya Tomaru, Hatoyama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Communications having high security against information leakage can be established in a current optical fiber network in the following manner. (1) A sender and a receiver share a seed key in advance, and then transmit and receive random numbers superimposed on carrier light accompanied with fluctuations, where transmission basis is determined by a random number. The sender and the receiver check a shared basis determined by the seed key with a random basis and employ only a random number signal superimposed on a slot for the shared basis that coincides with the random basis, and share the random numbers between the sender and the receiver. Here, since the carrier light has fluctuations, a bit error exists in the received signals. However, because of the seed key, a legitimate receiver can receive a signal with a bit error rate smaller than an eavesdropper. (2) The information amount of the random numbers shared between the sender and the receiver is reduced to secret capacity through privacy amplification, and then the reduced random numbers are set to be a secret key. (3) An actual signal is encrypted with the obtained secret key, and is transmitted and received.