1. Apparatus which authenticates a digital representation from which an analog form may be made, the apparatus comprising: an authenticator which uses semantic information in the digital representation that will be present in the analog form to produce first authentication information; and an incorporator which incorporates the first authentication information into the digital representation such that the first authentication information is preserved in the analog form and the semantic information remains useful in the analog form to produce second authentication information which is comparable to the first authentication information, whereby the first authentication information may be retrieved from the analog form and compared with the second authentication information produced from the semantic information in the analog form to determine authenticity of the analog form.