The utopia of a paper-less society is just that: utopia. The reality is that we are swamped with papers. Bureaucracy vs. papers is like fish vs. water. Decisions, Reports, critical data of all sorts is written and evaluated from and to paper documents, and this reality is a bonanza for fraudsters, forgers, and ill-intent characters of all sorts.

Digital data has been successfully protected against all but the most skillful adversaries: encryption and data signatures safeguard the integrity of electronic files. By contrast, it takes minimal skills to scribble a forged phrase onto a paper document, or to add a zero to a printed number. Once a paper is released to a third party, even for the purpose of carrying it to an intended recipient -- there is little in terms of assurances that the image on that paper was not tampered with. Bills, invoices, certificates, awards, credentials-stating documents, access-granting papers -- constitute a fertile ground for ill-wishers to execute their schemes and interfere with the good order of public life.

if.Pi: Iterative Framing of Paper Image, is a simple and effective solution to paper integrity. It works by scanning the page in question, and then reducing the image into a short digital signature that is affixed on the page in the form of a bar-code label. Any recipient of the document would scan it, reduce the scan to its signature, and compare it to the label. If the two signatures disagree, then the document was forged.

On its face, this is very similar to data signatures for electronic files, but in reality the paper challenge is much more formidable for two reasons. First, when you scan the same paper twice, even through the same scanner, you don't get the same bit-sequence. A slight tilt, or shift in the position of the paper, and the electronic version is somewhat different. And since data signatures are very sensitive to even one flipped bit, this variance between scans makes it impossible to compare the label to a more recent scan (especially if done through a different scanner), unless one circumvents this variance, which is what if.Pi does.

Second, unlike electronic files, papers suffer from normal and innocent abuse: they get folded, wrinkled, take on coffee stains, ink-smears, etc. The solution would have to be smart enough to distinguish between such harmless changes, and a bona fide forgery. if.Pi does it.

if.Pi extends the power of data security to data on paper.