Patent ID: 6934839
Filing Date: 2005-08-23
Classification: G07B,H04L

Abstract:
1. A method for evidencing payment of indicia using secret key cryptography in a system including a plurality of indicia generating devices that are divided into groups, each group corresponding to a respective geographic designation, each of the indicia generating devices for generating and printing indicia on a media that is to be received at a plurality of establishments, wherein the establishments are associated with different geographic designations, the method comprising: (a) assigning a set of verification keys from among a plurality of verification keys to each indicia generating device in each of the groups, wherein each set of verification keys assigned to the groups is encrypted as a function of respective geographic designations; (b) associating a key ID with each of the verification keys and encrypting each key ID as a function of the same geographic designation used to encrypt the corresponding verification key; (c) distributing to each one of the establishments in the respective geographic designations via the network, the set of verification keys and associated key ID's that were encrypted as a function of the geographic designation associated with the establishment; (d) assigning to each group of indicia generating devices, at least one respective secret key from a set of secret keys, and distributing the assigned secret key to each indicia generating device in each group of indicia generating devices; (e) using one of the indicia generating devices to generate indicia for media destined for a particular one of the establishments, and evidencing the indicia by (f) upon receiving the media at the particular establishment, verifying the indicia on the media using the key ID on the indicia and the distributed verifications keys to compute a digital signature, and comparing the computed digital signature with the digital signature on the indicia.