Electronic copy protection mechanism using challenge and response to prevent unauthorized execution of software

Patent 5935246 Issued on August 10, 1999. Estimated Expiration Date:

April 11, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventor

Benson, Glenn Stuart

Assignee

International Computers Limited

Application

No. 838620 filed on 04/11/1997

Examiners

Primary: Kizou, Hassan
Assistant: Mai, Rijue

Attorney, Agent or Firm

Lee, Mann, Smith, McWilliams, Sweeney & Ohlson

Foreign Patent References

WO 88/05941 WO. 08/13/1988

International Class

G06F 012/14

Foreign Application Priority Data

1996-04-26 GB

Abstract

A copy protection mechanism for protecting software against copying, consists of a challenge mechanism embedded in each protected item of software. The challenge mechanism has no access to the customer's private keying material. In operation, the challenge mechanism sends a random challenge to the customer's signature server. The signature server signs the challenge, using the customer's private keying material and then returns the signed challenge to the challenge mechanism. The challenge mechanism then verifies the signed challenge, using the customer's public keying material, and prohibits the customer from using some or all of the protected item of software unless the verification is successful. The mechanism permits every customer to receive an identical copy of the copy protected program with the embedded challenge mechanism.