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:
Dec. 04, 2012
Filed:
Nov. 29, 2007
Alain Durand, Rennes, FR;
Alain Durand, Rennes, FR;
Thomson Licensing, Boulogne-Billancourt, FR;
Abstract
Device and method for calculating distance in a communication network. Device A sets a non-predictable initial Time-To-Live (TTL) value and sends a message with this value to device B. B reads the TTL of the received message. A and B establish a Secure Authenticated Channel over which B sends the TTL of the received message. A may then calculate the distance to B. If the received TTL is greater than the initial TTL, this indicates an error or an attack; if the received TTL is lower than the initial TTL minus a TTL limit, then B is too distant; and if the initial TTL minus the TTL limit is less than or equal to the received TTL, which in turn is less than or equal to the initial TTL, then A may conclude that B a priori is within the required distance.