A METHOD OF GENERATING AND VALIDATING A VOUCHER THAT IS USED TO ENABLE AN END-USER TO OBTAIN GOODS OR SERVICES

摘要

A method of generating and validating a voucher to enable an end-user to obtain goods or services, comprising: (a) generating or acquiring contextual data that describes the goods or services and then encrypting that contextual data at a server or other device; (b) generating a time code corresponding to a span of time during which the voucher is valid and including or concatenating that time code with the contextual data; (c) signing the contextual data and time code cryptographically using either a symmetric or asymmetric secret key or keys to generate a signature; (d) providing the contextual data and time code and/or the signature on a voucher; (e) validating the voucher offline at a validating system, without having on-line access by means of comparing the signature in a process using a locally stored key shared with the server or other device that encrypted the contextual data.