Pieces of information are multiplexed in a plurality of portions on an image respectively. Image information which sets an edge amount becomes equal to or larger than a threshold is multiplexed in a portion of the plurality of portions where an edge amount is smaller than the threshold.

Systems and methods are directed towards generating a verified unique watermark. More specifically, the systems and methods are directed towards generating a watermark that is as long as possible without any repetition. Such watermarks are possible by selecting characteristics of the watermark and methods for producing the watermarks (e.g., dandy rollers). By producing longer unique watermarks, users would be capable of generating longer rolls of paper whereby more sheets can be produced that each possesses a unique watermark. With the unique watermark, users can identify what information is printed on each sheet as well as authenticate the contents of each individual sheet.

Methods for certifying a security document comprising the steps of: a) selecting a set of unique characteristics, obtained as the result of the variations in the manufacturing process and supplies, b) getting a digital image of a security document and obtaining data of the relative position between features selected from different manufacturing processes (register), c) constructing a message by measuring the register of selected features from the document and the document ID data, d) constructing a hashed message, the hashed message being the message obtained after being encoded by means of a unidirectional cryptographic hash function, e) encrypting the hashed message using a public key cryptographic system to obtain a digital certificate by means of a private key, and f) storing the digital certificate in an external database.

Systems and methods are directed towards generating a verified unique watermark. More specifically, the systems and methods are directed towards generating a watermark that is as long as possible without any repetition. Such watermarks are possible by selecting characteristics of the watermark and methods for producing the watermarks (e.g., dandy rollers). By producing longer unique watermarks, users would be capable of generating longer rolls of paper whereby more sheets can be produced that each possesses a unique watermark. With the unique watermark, users can identify what information is printed on each sheet as well as authenticate the contents of each individual sheet.

Systems and methods are directed towards generating a verified unique watermark. More specifically, the systems and methods are directed towards generating a watermark that is as long as possible without any repetition. Such watermarks are possible by selecting characteristics of the watermark and methods for producing the watermarks (e.g., dandy rollers). By producing longer unique watermarks, users would be capable of generating longer rolls of paper whereby more sheets can be produced that each possesses a unique watermark. With the unique watermark, users can identify what information is printed on each sheet as well as authenticate the contents of each individual sheet.

Systems and methods are directed towards generating a verified unique watermark. More specifically, the systems and methods are directed towards generating a watermark that is as long as possible without any repetition. Such watermarks are possible by selecting characteristics of the watermark and methods for producing the watermarks (e.g., dandy rollers). By producing longer unique watermarks, users would be capable of generating longer rolls of paper whereby more sheets can be produced that each possesses a unique watermark. With the unique watermark, users can identify what information is printed on each sheet as well as authenticate the contents of each individual sheet.

Pieces of information are multiplexed in a plurality of portions on an image respectively. Image information which sets an edge amount becomes equal to or larger than a threshold is multiplexed in a portion of the plurality of portions where an edge amount is smaller than the threshold.

Some implementations may provide a computer-implemented method for validating a digital document, the method including: receiving, at a computing device, the digital document comprising at least two digital watermarks, the digital document issued by a central entity; retrieving a first digital watermark from the digital document, the first digital watermark visually presented at a first time point; retrieving a second digital watermark from the digital document, the second digital watermark visually presented at a second time point, the second digital watermark being different from the first digital watermark and the second time point being different from the first time point; and reading the digital document based on the retrieved first and second digital watermarks.

An image processing apparatus includes: a first obtaining unit configured to obtain an original image; a second obtaining unit configured to obtain region information indicating first and second regions, the first region read in reading of a print original to have a higher density than the second region, the second region read in the reading to have a lower density than the first region; an embedding unit configured to embed information in the original image by embedding a pattern with a directivity in the first region and embed, in the second region, a pattern in which the number of pixels printed adjacent to printed pixels is smaller than that in the first region; and a control unit configured to perform control of outputting the print original by using a print image in which the patterns of the first and second regions are embedded by the embedding unit.