We will merely present a few types and principles of techniques. It would take hundreds of pages to detail all of them.
Machine-readable zone (MRZ)
Used on a wide range of documents, these 2-3 lines of characters using chevrons for spaces contains some of the information in the document: bearer’s identity, birthdate, document expiration date, document number, etc. It has the added value of checksums, verification of which proves useful.
Ink – whether fluorescent, fugitive, iridescent, metallic, optically variable, photochromic, bleeding (penetrating) or even thermochromic – plays a very important role in securing an identity document.
Special character fonts
A special character font not available in the public domain can be used as an additional security component.
Barcode / two-dimensional barcode
Barcodes have appeared on identity documents for many years. First one-dimensional, now they come as 2D, often in PDF417 format. The 2D-DOC code invented by AriadNEXT was presented to the ICAO, and its adoption for some identity documents is under consideration.
Printing techniques used for the document background or to personalize the document are significant security elements, even if it is often difficult to verify them with the naked eye: offset, intaglio printing, letterpress and screen printing for the background, laser and inkjet printing and thermal transfer for personalization.
Mini- or microprint
Printing a very small text – difficult to accurately reproduce with a standard printer – is a relatively effective security element.
Integration of a chip (contact or contactless)
Set into a polycarbonate card or the cover of a passport, an electronic chip provides an important security element to the document, in addition to the additional features it may offer a document, such as verifying the bearer’s fingerprints.
Components responding to special lighting or special document viewing angle
In this category we find designs responding to ultraviolet light or those disappearing under infrared, holograms, fluorescent planchettes, and more.
Depending on the quality of the images sent to it for analysis, the IDCHECK.IO service employs verification algorithms allowing it to check the most relevant security elements.