Electronic data protection system

Patent 5392351 Issued on February 21, 1995. Estimated Expiration Date:

March 15, 2013. 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

Method and device for protecting software delivered to a user by a supplier
Patent #: 4683553
Issued on: 07/28/1987
Inventor: Mollier

Code protection using cryptography
Patent #: 4757534
Issued on: 07/12/1988
Inventor: Matyas , et al.

Controlled use of cryptographic keys via generating station established control values
Patent #: 4850017
Issued on: 07/18/1989
Inventor: Matyas, Jr. , et al.

Metering retrieval of encrypted data stored in customer data retrieval terminal
Patent #: 5010571
Issued on: 04/23/1991
Inventor: Katznelson

Method of distributing computer data files
Patent #: 5058162
Issued on: 10/15/1991
Inventor: Santon, et al.

Method and apparatus for protecting material on storage media Patent #: 5065429
Issued on: 11/12/1991
Inventor: Lang

Inventors

Assignee

Fujitsu Limited

Application

No. 031339 filed on 03/15/1993

US Classes:

705/51, Usage protection of distributed data files380/277, KEY MANAGEMENT713/193By stored data protection

Examiners

Primary: Barron, Gilberto Jr.

Attorney, Agent or Firm

Nikaido, Marmelstein, Murray & Oram

Foreign Patent References

0114522 EP. 08/13/1984
0268139 EP. 05/13/1988
3-83132 JP. 04/13/1991
88-02202 WO. 03/13/1988

International Class

H04L 009/32

Foreign Application Priority Data

1992-03-16 JP

Abstract

An electronic data protection system for protecting electronic data from illegal copying by a third party, includes: a storage medium for storing an encrypted electronic data, a medium number and encrypted permission information; a vendor computer having a personal key generating unit for generating a medium key based on the medium number, an electronic data decrypting key, and an encrypting unit for encrypting the electronic data decrypting key based on the medium key to generate the encrypted permission information; and a user computer having a personal key generating unit for generating a medium key based on the medium number, a decrypting unit for decrypting the encrypted permission information based on the medium key to generate the electronic data decrypting key which is the same as the electronic data decrypting key of the vendor computer, and a decrypting unit for decrypting the encrypted electronic data based on the electronic data decrypting key to generate a plain text electronic data.