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:
May. 10, 1994
Filed:
Jul. 02, 1992
David M Claus, Indianapolis, IN (US);
Kevin D Murphy, Indianapolis, IN (US);
Marjorie E Taylor, Carmel, IN (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
A secure toll payment system is realized by transmitting a changeable encryption code from roadside equipment at a toll plaza to a moving vehicle. Thereafter, the moving vehicle uses it to encrypt payment information according to the Data Encryption Standard algorithm. The moving vehicle transmits the encrypted payment information to the roadside equipment which performs a credit or debit transaction. Because the encryption code changes from time to time, so too does the nature of the signal which is transmitted by the vehicle; and fraud, based on electronic eavesdropping, is substantially eliminated. The encryption code comprises an 8-bit random number and a time/date number. Vehicle-mounted apparatus includes a transponder unit and a portable smart card which inserts therein. The roadside equipment includes a pair of spaced-apart antennas that are sequentially located along an express payment lane at a toll plaza and a computer (Plaza Server) which controls them.