Secured printer for a value printing system
US4813912A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 1986 |
| Grant date | Mar 21, 1989 |
| Priority date | — |
| Expiry date | Sep 2, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07B2017/00741
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A system is disclosed for securing a device from invasive and noninvasive tampering, one such device being a printer assembly for use in a value printing system, such as a postal mailing system. The system is comprised of a Decryption Microcomputer operable for decrypting the input data to be printed in accordance with a valid cipher key, the encrypted data and key being provided by another device, such as a postal meter. The cipher key is stored within a Tamper Latch readably coupled to the Microcomputer for providing the key to the Microcomputer. In addition, the Tamper Latch has a wire of small cross-sectional area connected thereto such that the presence of the wire is operable for defining a portion of the cipher key. To provide further security from tampering the Microcomputer, Latch and wire are embedded within a potting material. An attempt to remove the potting material in order to gain access to the components embedded therein will cause a brakage of the wire, thereby invalidating the cipher key and rendering the Microcomputer inoperable for decrypting the data to be printed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.