Document verification: Could chipless RFID be used for secure document exchange?

Document verification refers to determining the authenticity of a document, and this can occur, for example, in relation to employment processes. An officially issued document, such as a passport or driving license, can be presented for verification, wherein the validity of such data as ‘name’ and ‘age’ will be checked. The document features themselves will also be under examination, to find faults or signs of forgery in watermarks, fonts, etc. There are two common types of forgeries that pose an issue today: those posed by re-engineered documents and those that are made by scanning, and then print a copy of a legitimate document.

In the past, customers were always required to be physically present for document verification. The digital age has brought about significant change in this area. In online banking, for example, customers can upload photographs or scans of government-issued documents and verify information via phone calls.

Technology aids in document scanning, particularly by reducing certain problems. Mistakes because of human exhaustion are made impossible, sophisticated frauds that the naked eye cannot catch can be processed and associated costs are reduced. Further benefits include connections to databases around the world, faster services, and scalability.

What is RFID?

RFID stands for radio-frequency identification. This identification method uses electromagnetic waves to identify and track tags. A scanner will emit electromagnetic waves for the tag to receive, and return, through an antenna. Credit cards have RFID tags, allowing us to simply hold them near a reader to be activated. Historically, a form of RFID was used by the allied forces during the Second World War, whereby a transponder would react to radar by returning its signal as a marker of ‘being on the same side.

Secure document verification has been a focus of researchers for many years, especially those involved with government agencies. There is a demand for affordable security printing, such as banknotes and ID cards.

How do you implement a chipless system?

Some developers have proposed a way to verify documents using chipless RFID systems. First, a chipless RFID tag would be printed into the document paper. A frequency scanning, within a particular GHz spectrum, would then transfer the data as a scattered parameter to a cloud database, and the document receiver would verify the frequency through the same scanning method. The receiver’s scanning would send the scattered data to the cloud to receive back the decoded data. The document is verified if the decoded data is as expected. This is presented as a secure and scalable solution.

Although chipped tags remain a viable option for ePassports, as an example of an extremely sensitive document, to protect against fraud, they are not cheap. It is also possible for these chips to be read by RFID spy readers. Some chips are rewritable, so RFID information can be replaced with the hacker’s chosen data. Therefore, chipless RFID systems may be the next step. They can be printed at a micro-millimeter thickness within papers or plastics and can be designed against this.