Evidencing indicia of value using secret key cryptography

Abstract

A method and system for dispensing and evidencing indicia by an indicia generating device is disclosed in a system having a plurality of indicia generating devices that have been divided into n groups. Each of the indicia generating devices generates and prints 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 and system include receiving a plurality of verification keys, wherein each one of the received verification keys is encrypted as a function of a respective geographic designation. A plurality of key IDs are also received, where each one of the key IDs is associated with one of the verification keys and is encrypted as a function of the same geographic designation used to encrypt the corresponding verification key. In response to receiving a request to generate an indicium for a media destined for a particular one of the establishments, the indicia generating device evidences the indicium by generating one of the verification keys and the corresponding key ID assigned to indicia generating device's group based on the geographic designation associated with the particular establishment, and using the generated verification key to create a digital signature, and digitally signing the indicia by including the digital signature and the generated key ID in the indicia.