1. An apparatus to authenticate 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 apparatus comprising: a first reader configured to determine the first plural-bit message based on the first machine-readable information and determine the second plural-bit message based on the second machine-readable information; a second reader configured to determine authentication information from the semantic information carried on or in the identification document; and an electronic processor configured to: decrypt the first plural-bit message or the authentication information; and determine 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.
1. An apparatus to authenticate 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 apparatus comprising: a first reader configured to determine the first plural-bit message based on the first machine-readable information and determine the second plural-bit message based on the second machine-readable information; a second reader configured to determine authentication information from the semantic information carried on or in the identification document; and an electronic processor configured to: decrypt the first plural-bit message or the authentication information; and determine 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. 3. The apparatus of claim 1 , wherein the semantic information comprises data representing a photograph.