Abstract: A printer that prints encrypted information in a document can be the key authority for that document. A document containing encrypted information and a source reference can be printed by a printer associated with a key module. The key module contains the key for decrypting the information. A scanner scanning the document obtains the source reference and the encrypted information. The scanner can use the source reference to send a key request to the printer and the printer can respond with the appropriate key. A decryption module associated with the scanner can use the key to decrypt the information. The decrypted information can be incorporated into a second document that can be electronically stored or printed.

Abstract: A method for performing optical character recognition (OCR) on an image of a document including text includes embedding a physical manifestation of digital information associated with the text on the document. When the document is scanned with a scanning device, the digital information and a digital text file are produced. The digital text file is proofed using the digital information.

Abstract: The disclosure recites methods for verifying that the authenticity of a hard copy document by verifying that a digital signature printed on that document matches the signature on the original electronic document. The method includes converting a physical manifestation of a digital signature affixed to the hard copy document to an electronic digital signature, validating the electronic digital signature via a public key to authenticate the hard-copy document, and comparing a message digest of the original electronic document to a message digest coded in the digital signature. It also includes documents having multiple digital signatures embedded using a variety of techniques, converting those printed digital signatures into electronic forms, and validating each electronic digital signature independently and against each other.