Printing and validation of self validating security documents

The present invention relates generally to identification documents. One claim recites an apparatus to authentic an identification document. The identification document comprising first machine-readable information including a first plural-bit message, and semantic information carried on or in the identification document. The apparatus includes: a first reader to read the first machine-readable information to obtain the first plural-bit message; a second reader to obtain information from the semantic information carried on or in the identification document; an electronic processor programmed as a decryption unit to decrypt the first plural-bit message or the information obtained from the semantic information; and an electronic processor programmed as a decision unit to determine whether the identification document is authentic based at least in part on the first plural-bit message and the semantic information. Other claims and combinations are provided as well.