The LowResTrack&Trace™ technology

This technology belongs to the family of voluntary created chaos devices. It therefore implies that a picture of the device is taken after its production (by printing it) and that a description is stored for comparison with another picture taken at the time of authentication.
Advantageously, each of the two procedures, enrollment and authentication, can be achieved by with a simple smartphone. One therefore takes a picture of the device after printing, that can be also accompanied by a photo of the entire document, and stores it with the smartphone application on a remote server. Authentication is also done with a smartphone application that acquires the device to verify that it is similar to the one which was stored. The case where two signatures of two different devices are identical does not matter, since one only wants to verify the correlation between the signature of a device with that of a device with the same ID, which is for example a bar code.

Printing in two steps

The first step is to print a simple pattern like the one shown below to the left inside a red frame, on all sheets of a ream of paper.
This provides a series of media that can be used to print on demand and instantly documents that may be authenticated with a simple smartphone.
   

The second step is printing the document itself, which includes the printing at the same location of an identifier and of the second part of the LowResTrack & Trace™ device. This second part is shown on the the left, also inside a red frame.
The two semicircles patterns sets cannot be perfectly aligned, for two reasons:
firstly because it is unlikely that the positioning of the sheet in the printer is perfectly identical from one print to another, (converters call this the "registration"), and only highly qualified printers can maintain a perfect registration.
and secondly because, in any event, if one of the two sets is perfectly aligned, the other is not. This is because that the semicircles patterns are not the same distance apart from each other between the two successively printed patterns.
The superposition of the two patterns results in two characteristics. It is randomly organize, and the result is also very difficult to reproduce, because it is not printed at the resolution of the printer, but at a much higher resolution.

Even quicker if you have a stamp

It's even more simple : you just print the barcode with the first semicircles pattern. These elements can be added automatically to your letters when you wish.
Then, just apply the second semicircle pattern on the first one with a stamp, and enlist your document in the secure database. That's all!

The difficult reproduction is adapted to many use cases

Below is a comparison between the print obtained by printing in two steps, and an attempt to reproduct the result with the same printing device, but in only one single step since it is practically impossible to intentionally obtain the same offset between the two successive impressions:
 
Small colored surfaces appear red in the same locations in the two images. On the original, these colored areas are shown on the surfaces that are white because they did not receive any ink. On the attempted reproduction, these areas are too small to have been left blank because of the capillary action of the ink on the one hand but also because of the insufficient resolution of the printer to achieve this. One advantage of this technology is that it is not necessary to store a photography of the entire device in the database, since it is sufficient to note the coordinates and surfaces of these small virgin areas.
It is of course possible to make devices that may be authenticated locally, by noting in an encrypted form in the coordinates identifying these small blank surfaces observed after printing. This local authentication can be complemented by an online authentication for a very secure removal of doubt.

A good converter could of course reproduce the original with a sufficient quality, and even print thousands of copies. It is not even necessary for him to have HD qualifications, since a resolution of about 2400 DPI, which is very common, is enough to deceive any human eye and any smartphone. The acquisition resolution of an iPhone 5 type smartphone does not in fact exceed 1200 DPI: a high-end sensor, 8 megapixels, capturing a 70mm wide surface in landscape format, carries an image of 3,264 pixels or 0.02 mm/pix, which corresponds to a resolution of about 1200 DPI.

This technology is not suited to the fight against counterfeiting, but it is sufficient to prevent amateurs from photocopying or reprinting the most commonly faked documents such as invitations, parking tickets, diplomas, medical certificates and prescriptions, voter cards, pay slips, insurance certificates, loyalty cards, tax certificates, meal vouchers and other prepaid titles, transport or show tickets, etc..

Implementation

Integrators authorized by PopimsCode to use this technology will grant their clients with ranges of identifiers, as part of a service that includes data storage and answering to authentication requests. The service can be paid or free and financed through advertising.
The identifier of the device can be either a string or a barcode. In the second case, a barcode generator can be provided by the integrator, but there are already many available on the market, both for professional printing systems than those included in office software like "Microsoft Office". Advantageously, the identifiers generation may be coupled with the payment of the codes enlistment in the database and of the authentication.
The PopimsCode and PopimsCard applications will both enable the enlisting and instant authentication of these devices but professionals printing large series of codes will prefer adding an industrial camera output of their printing systems.