Patent · US Expired

Postage security device having cryptographic keys with a variable key length

US6868407B1 · kind B1 · utility

13Cited by
15References
19Claims
0Family size

Assignee

Inventor

Key dates

Filing dateNov 2, 2000
Grant dateMar 15, 2005
Priority date—
Expiry dateJun 13, 2022

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG07B2017/00967
  • WIPO fieldControl
  • WIPO sectorInstruments

Abstract

A cryptographic method for providing a level of security by a postage security device, which generates a digital token using a cryptographic key. When it is required to make a key change in order to improve the level of security, the postage security devices replaces the cryptographic key with a new cryptographic key, wherein the new cryptographic key has a key length that is equal to or greater than the replaced cryptographic key. The new cryptographic key can be generated by the postage security device based on a given key length, or selected from a plurality of replacement keys stored in a storage device.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.