Copy prevention apparatus and method therefor
US5027398A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 24, 1990 |
| Grant date | Jun 25, 1991 |
| Priority date | — |
| Expiry date | Apr 24, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F21/123
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In the copy prevention apparatus and its method, it is discriminated whether an object is legally copied or not; a constant event is generated at or below a predetermined probability; and an abnormal operation is executed only if the two conditions of the object having been determined as an illegal copy, and the event having been generated, are satisfied. Therefore, even if the object is determined as an illegal copy, the abnormal operation is not always executed, but executed at or below a predetermined probability. Although the occurrence of the abnormal operation can be indicated to the user immediately, it is also preferable to keep the abnormal operation occurrence secret for a time and inform the user of the occurrence an appropriate time later.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.