Decryption device
US5056142A · kind A · utility
Inventors
Key dates
| Filing date | Nov 30, 1989 |
| Grant date | Oct 8, 1991 |
| Priority date | — |
| Expiry date | Nov 30, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09C1/04
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A decryption device, comprising a substrate, a plurality of encrypted information symbols located within a rectangular array of further symbols carried by the substrate, wherein the array is arranged in a predetermined number of rows by a further predetermined number of columns. A pair of registration marks are carried by the substrate and located on opposite sides of a predetermined one of the rows. An overlay is adapted for covering the rectangular array, and includes a first pair of apertures arranged to uncover the pair of registration marks, and a plurality of further apertures arranged to uncover the plurality of encrypted information symbols responsive to the first pair of apertures uncovering the pair of registration marks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.