Self validating security documents utilizing watermarks

A security document comprising:

• a substrate having a portion conveying a steganographic digital watermark, the substrate having another, different portion conveying another, different stegano graphic digital watermark, the substrate also having a machine-readable feature distinct from said digital watermarks, said machine-readable feature conveying data relating to a document identifier;
• a first of said digital watermarks conveying data that corresponds in a predetermined manner with the document identifier, permitting data from said machine-readable feature and said first of said digital watermarks to be checked for expected correspondence so as to identify a document as potentially suspect;
• and
• said first of said watermarks also conveying data that corresponds in a predetermined manner with data conveyed by a second of said digital watermarks, permitting data from said first of said digital watermarks and said second of said digital watermarks to be checked for expected correspondence so as to identify a document as potentially suspect.

A printed article having a substrate conveying at least four machine-readable features:

• a first steganographic digital watermark;
• a second, different, steganographic digital watermark;
• a third feature;
• and
• a fourth feature;
• wherein a first set comprising three of said features are logically linked by reference to first data, and a second set comprising a different three of said features are logically linked by reference to second, different data.

A method of creating a photo identification document using a substrate, comprising:

• receiving an encoded photographic image, wherein the encoded photographic image comprises a steganographic digital watermark conveying a first payload;
• printing on the substrate, in a first region thereof, said encoded photographic image;
• forming on the substrate, in a second region thereof, another steganographic digital watermark conveying a second payload, the second region having at least a portion not encompassed by the first region;
• wherein the two watermark payloads convey data permitting cross-checking therebetween to identify a document as potentially suspect.

A method of checking a photo identification document, comprising:

• decoding first payload data from a steganographic digital watermark encoded in a first region of the document;
• decoding second payload data from a steganographic digital watermark whose encoding spans an area outside said first region;
• and
• checking for expected correspondence between said first and second payload data to determine whether the document is suspect.

A system for checking a photo identification document, comprising:

• a scanner for visible light scanning of the document to produce scan data corresponding thereto;
• a watermark decoder for processing said scan data to decode first payload data from a steganographic digital watermark encoded in a first region of the document;
• said watermark decoder also processing said scan data to decode second payload data from a steganographic digital watermark whose encoding spans an area outside said first region;
• and
• a processor for checking for expected correspondence between said first and second payload data to determine whether the document is suspect.

A physical article comprising:

• a first portion conveying first steganographic encoding;
• and
• a second portion conveying second, different steganographic encoding,
• the first and second steganographic encoding conveying data permitting cross-checking there between to aid in ascertaining authenticity of the article.

An apparatus to analyze an identification document, comprising:

• a decoder to process scan data to decode first payload data from steganographic encoding encoded in a first region of the document;
• said decoder to also process scan data to decode second, different payload data from steganographic encoding whose encoding spans an area outside said first region;
• and
• a comparator to check for an expected correspondence between said first and second payload data.