Complex document security
US5701342A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 1995 |
| Grant date | Dec 23, 1997 |
| Priority date | — |
| Expiry date | Aug 28, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/3278
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and means to control the degree to which the presence of covert information may be reduced, eliminated or corrupted in documents created on a computer device (particularly complex documents) before the document is transmitted outside a secure environment in which the document is created. The process of handling a document in a secure environment comprises the preferred step of displaying the document or a predetermined portion thereof in a manner which conforms to the rule that no pixel of the display is written to more than once for the current portion of the document being displayed. Preferably the method includes the steps of creating a document, transforming the document into an intermediate form by defining the content and structure of the document using a predetermined set of document describers, applying the intermediate form of the document to at least one filter adapted to eliminate or corrupt the content and form of any covert information contained within the intermediate form of the document followed by the previously described step of displaying the document in the manner described above.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.