Robert A. Cordery

Black fluorescent ink and applications

Black fluorescent inks developed for postal applications exhibit contrast suitable for machine reading and fluorescence suitable for postal processing. The combination of black color and red fluorescence in one ink requires inhibition of fluorescence quenching. One way to inhibit quenching is by combining subtractive dyes and leaving an absorbance window for the emission of the red fluorescence. The absorbance and emission spectra of the ink confirm the model. Another approach is combining larger size colorants: fluorescent and non fluorescent in order to lower the collision probability and quenching by energy transfer. The covert nature of the fluorescence lends itself to security applications.

HISTORY AND ROLE OF INFORMATION SECURITY IN POSTAGE EVIDENCING AND PAYMENT

ABSTRACT Step-by-step, information security technology has enabled the transition of postage evidencing and payment security from reliance on people, manual processes and paper records to reliance on automated procedures, trusted remote data systems and cryptographic protocols. This evolution improved both the security and the convenience of postage evidencing and payment through postage metering and thus enabled effective access to postal products. Reset, the process of adding postage to the meter, changed from a visit to a post office and manual record keeping to communication with a data center to receive an authentication code with a subsequent automatic completion of the transaction. Verification of the authenticity of printed indicia changed from a forensic analysis to automatic cryptographic authentication. Finally, with the introduction of NIST standard FIPS 140–1 level 4 physical security requirements, manual inspection of meters that are compliant with this standard by postal officials is being replaced by online verification of their physical integrity and procedural accuracy. These improvements in their totality enabled a remarkable transition of one of the most traditional office devices from the analog to the digital age.

Sub-pixel analysis to support graphic security after scanning at low resolution

Whether in the domain of audio, video or finance, our world tends to become increasingly digital. However, for diverse reasons, the transition from analog to digital is often much extended in time, and proceeds by long steps (and sometimes never completes). One such step is the conversion of information on analog media to digital information. We focus in this paper on the conversion (scanning) of printed documents to digital images. Analog media have the advantage over digital channels that they can harbor much imperceptible information that can be used for fraud detection and forensic purposes. But this secondary information usually fails to be retrieved during the conversion step. This is particularly relevant since the Check-21 act (Check Clearing for the 21st Century act) became effective in 2004 and allows images of checks to be handled by banks as usual paper checks. We use here this situation of check scanning as our primary benchmark for graphic security features after scanning. We will first present a quick review of the most common graphic security features currently found on checks, with their specific purpose, qualities and disadvantages, and we demonstrate their poor survivability after scanning in the average scanning conditions expected from the Check-21 Act. We will then present a novel method of measurement of distances between and rotations of line elements in a scanned image: Based on an appropriate print model, we refine direct measurements to an accuracy beyond the size of a scanning pixel, so we can then determine expected distances, periodicity, sharpness and print quality of known characters, symbols and other graphic elements in a document image. Finally we will apply our method to fraud detection of documents after gray-scale scanning at 300dpi resolution. We show in particular that alterations on legitimate checks or copies of checks can be successfully detected by measuring with sub-pixel accuracy the irregularities inherently introduced by the illegitimate process.