1. A method of producing and authenticating a secure document comprising the steps of: a) scanning said document to produce a first signal representative of an image of said at least a portion of said document; b) encrypting a second signal, comprising a representation of said image, said second signal being derived at least in part from said first signal; c) incorporating a coded representation of said encrypted second signal with said document; d) reading said coded representation of said second signal from said document; e) decoding said second signal; f) decrypting said decoded second signal; g) inputting said decrypted second signal to a display to display said representation of said image; h) comparing said document to said displayed image to authenticate said document.