Printer Security and Forensics

Several methods exist for printer identification from a printed document. We have developed a system that performs printer identification using intrinsic signatures of the printers. Because an intrinsic signature is tied directly to the electromechanical properties of the printer, it is difficult to forge or remove. These signatures are shown to be robust against several attacks models. In addition we have developed methods for embedding information into a text document using extrinsic signatures. Using these techniques we have been able to embed over 12kbits of information imperceptibly into a page of 12-point text.