Browse Prior Art Database

Method to Prevent Tampering with Time & Date

IP.com Disclosure Number: IPCOM000018724D
Original Publication Date: 2003-Aug-04
Included in the Prior Art Database: 2003-Aug-04
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Abstract

As electronic commerce becomes more prevalent, trusted tracking of Time & Date will be increasingly important. The solution to this problem is to implement a hardware protection circuit as part of the system's hardware clock to prevent unauthorized modification of the system clock, while allowing authorized updates.

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Method to Prevent Tampering with Time & Date

As electronic commerce becomes more prevalent, trusted tracking of Time & Date will be increasingly important

Time/date stamps on documents to prove creation date of the document or response to a query. Elapsed time for accurate billing/usage fees.

Today, back dating the document creation date can be easily accomplished by simply changing the date/time on the system. Even in system where the operating system does not provide facilities for altering date and time or where BIOS does not prevent altering date and time without administrator authority, it may still be possible to alter date and time by means of a program that directly alters the CMOS clock and then rebooting the system. In order to prevent back dating of documents, what is needed is a method of preventing unauthorized alteration of the CMOS clock. This disclosure describes a method of preventing unauthorized access to the hardware clock.

The solution to this problem is to implement a hardware protection circuit as part of the system's hardware clock to prevent unauthorized modification of the system clock, while allowing authorized updates. One solution is a simple blocking circuit that POST (Power On Self Test) could enable once the determination had been made that the system clock was not to be updated. Once enabled, this circuit would block all write accesses to the clock until the next system reset. The disadvantage to this approach, is that the circuit...