Apparatus and method for controlling access to software
US5933497A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1993 |
| Grant date | Aug 3, 1999 |
| Priority date | — |
| Expiry date | Jan 29, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F21/121
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Software is distributed without entitlement to run, while a separately distributed encrypted entitlement key enables execution of the software. The key includes the serial number of the computer for which the software is licensed, together with a plurality of entitlement bits indicating which software modules are entitled to run on the machine. A secure decryption mechanism contained on the computer fetches its serial number and uses it as a key to decrypt the entitlement information, which is then stored in a product lock table in memory. The distributed software contains a plurality of entitlement verification triggers. Each trigger is a single machine instruction in the object code, identifying a product number of the software module. When a trigger is encountered during execution, the computer checks the product lock table entry corresponding to the product number of the software. If the product is entitled to run, execution continues normally; otherwise execution is aborted. Because this verification involves only a single machine instruction, it can be done with virtually no impact to overall system performance. As a result, it is possible to place a substantial number of suc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.