Tamper-resistant authentication techniques for identification documents

摘要

The present invention provides techniques that are helpful in resolving the authentication of an identification document or banknote. The document or banknote includes a security enhancer. The enhancer can be a graphic or artwork design, or can be realized with line art. In the case of an identification document, the spatial characteristics of the security enhancer are preferably altered in accordance with information contained in the identification document. For example, if the ID document includes a photograph, a hashing algorithm will reduce the photograph to a number. The number is used to set a repeated spacing distance of elements in the security enhancer. The repeated spacing yields an identifiable frequency response that is related to the identification document photograph.