Signature-embedding in printed documents for security and forensic applications

Despite the increase in email and other forms of digital communication, the use of printed documents continues to increase every year. Many types of printed documents need to be "secure" or traceable to the printer that was used to print them. Examples of these include identity documents (e.g. passports) and documents used to commit a crime. Traditional protection methods such as special inks, security threads, or holograms, can be cost prohibitive. The goals of our work are to securely print and trace documents on low cost consumer printers such as Inkjet and electrophotographic (laser) printers. We will accomplish this through the use of intrinsic and extrinsic features obtained from modelling the printing process. Specifically we show that the banding artifact in the EP print process can be viewed as an intrinsic feature of the printer used to identify both the model and make of the device. Methods for measuring and extracting the banding signals from documents are presented. The use of banding as an extrinsic feature is also explored.