Electronic indicia in bit-mapped form

Abstract

An item bearing bit-mapped indicia with information encrypted by a public key which verifies a status of the item and a method and apparatus for applying such indicia. The indicia represents an encrypted message and has the form of an array of pixels, each pixel having a value selected from a predetermined set of values in accordance with a mapping of an encrypted message on to the array. Thus, a person having knowledge of the appropriate decryption key may scan the indicia to obtain the message and verify the status by decrypting the message. In one embodiment disclosed, the item is a mail piece and the status is the payment of postage. The indicia may have the form of a binary matrix transformed by matrix multiplication by a corresponding Hadamard matrix and the encrypted message may be encrypted using a public key encryption system.