Method and apparatus for enabling trial period use of software products: method and apparatus for utilizing an encryption header
US5757908A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 4, 1996 |
| Grant date | May 26, 1998 |
| Priority date | — |
| Expiry date | Sep 4, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/0021
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus is provided in a data processing system for securing access to particular files which are stored in a computer-accessible memory media. A file management program is provided as an operating system component of the data processing system. A plurality of files are stored in a computer-accessible memory media, including at least one encrypted file and at least one unencrypted file. For each encrypted file, a preselected portion of the file is recorded in memory, a decryption block is generated which includes information which can be utilized to decrypt the file, and the decryption block is incorporated in the file in lieu of the preselected portion which has been recorded in memory. Then, a file management program is utilized to monitor data processing system calls for files stored in the computer-accessible memory media. The file management program determines whether the called file has an associated decryption block. The called file is processed in a particular manner dependent upon whether or not the called file has an associated decryption block.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.