14. The method of claim 10 , wherein the first reader and the second reader are configured to process optical scan data.
10. A method of authenticating an identification document, the identification document comprising: an image including steganographically encoded first machine-readable information including a first plural-bit message, a background including steganographically encoded second machine-readable information including a second plural-bit message, and semantic information including authentication information carried on or in the identification document, the method comprising: determining, using a processor, the first plural-bit message based on the first machine-readable information; determining the second plural-bit message based on the second machine-readable information; determining the authentication information from the semantic information carried on or in the identification document; decrypting the first plural-bit message or the authentication information; and determining whether the identification document is authentic based at least in part on the first plural-bit message, the second plural-bit message, and the authentication information, wherein the second plural-bit message comprises information from the first plural-bit message and the authentication information.