Definitions
RFID stands for Radio Frequency Identification, and it’s usually used in the context of a chip! There are active and passive types: an active RFID chip has a tiny battery with it, while a passive one is powered by the energy of the reader’s signals alone. Active chips can be read from much greater distances, but the battery makes them heavier and more expensive. Meanwhile passive chips have to be blasted with the RFID signal to be read.
How do they work?
RFID chips are great because they’re small, and they don’t take line-of-sight to read like many other cataloguing techs do.
There are three major parts to an RFID chip: the microchip, an antenna for receiving and broadcasting signals, and substrate to hold it together. RFIDs work with radio waves, a form of electromagnetic radiation. They actually got their start during the end of WWII, where a Soviet engineer created a passive listening device activated by radio waves, which would then store a small amount of information about the transmission. It wasn’t really the same as what we use in security tags and inventory systems today, but it was a tiny passive chip with information stored on it passively, and that’s close enough! 1973 saw a real attempt at the kind we have today, and ever since, they’ve been shrinking in size.
RFID chips can also come with read-only or read/write memory, depending on the style of that chip. Essentially, it has a very small amount of memory on it, just enough to store things like batch number, serial number, or address, in the case of pet tags. They’re not very complex: in the case of an active tag, the reader simply dings the RFID chip, which then responds on a compatible wavelength with the relevant information via that antenna.
Some chips broadcast constantly, while others broadcast on a regular interval, and some wait for the RFID reader to ding them before they send their data. In a passive chip, the RFID reader has to ding the chip so hard that it absorbs enough EM radiation to respond – energy hits the antenna, travels to the chip, and powers it enough to activate the antenna for signalling, which then causes the chip’s signal to travel back up the antenna and transmit to the reader. Neat!
Utility
An RFID chip’s low profile and small size makes them great for inventory management. Since the chip doesn’t need line-of-sight like barcode scanners do, production doesn’t have to worry about maintaining a certain orientation towards cameras for their items, they can just pass them over an RFID scanner and they’re good to go. Radio waves can pass through solid objects!
The RFID chips are also good at tracking inventory while in the store: you’ll notice many big box stores have an exit with detectors alongside the doors, which prevents unscanned or active chips from getting out the door. It also sometimes triggers on nametags and items the cashier had to scan in the cart, but most of the time it works as intended.
RFID chips are great for livestock and pet chipping – they’re small, and not only are they less painful than a tattoo, the data is also unlikely to migrate or blur like ink could in a pet’s ear. The initial wound is also smaller, which makes infection less likely. That doesn’t mean they’re perfect, but they carry a lot more information for less relative risk to the animal.
On the human side, RFID chips are frequently used in employee identification badges – the theory is that it’s harder to copy and easier to read than a barcode scanner for restricted areas. Some people go so far as to get them implanted, but the ethics of that are… iffy, to say the least, even if they want the implant. The long-term effects in humans just aren’t that well-known, and while pets are a good indicator that nothing should go wrong, pets also don’t have to worry about getting their phone hacked because their pet tag carried a virus along.
RFID chips are now popular in credit cards! The chip in the card is (in theory) safer than the regular magnetic stripe, and it’s supposed to be much harder to copy. Of course, early versions still had their issues, but now they’re difficult to signal from a distance.
Flaws
RFID chips aren’t free from flaws.
Security can be a problem, especially for active chips, which can be read from hundreds of meters away. Most vendors have some sort of protocol in place, but for a hot minute, RFIDs in cards were a potential security nightmare. Remember all those anti-RFID chip wallets? That’s because readers were able to access the chip as though they were being used for a purchase. It just wasn’t very safe before protocols were established.
Secondarily, a bunch of folks went out of their way to prove that the more complex RFIDs could become transmission sites for computer viruses – one guy had one implanted in his hand, and if the virus could infect that hand, then the virus could get anywhere he could wirelessly. The perfect crime! Airgapped networks were no longer safe if RFIDs were on the table.
Incompatible readers can make inventory transfers more painful than they need to be, as well – the ISO sets standards for which channels get to be used for what purposes, but the companies have to comply with them first. They also have to have the right kind of reader – is it scanning for active or passive chips? The two have very different needs. An active reader might not be able to find a passive chip!
There’s also the sticky issue of privacy and destruction. How do you get rid of the tag on the product once it’s no longer needed for inventory? RFIDs can be destroyed by microwaves, but that doesn’t help if they’re attached to an electronic, which can also be destroyed by microwaves. They can be wrapped in foil a couple of times, and stop transmitting long distances – on some objects, that makes them unusable. It takes special equipment and some professional skill to actually scan a building for RFIDs, but it’s not totally impossible.
It just takes work, the kind of work a stalker or government agent might be willing to put in if they needed info on a person so badly that they’d want to see what items they had in their house. This is also more difficult than it sounds because most chips go by something vaguely specific, like a batch or serial number with no product name attached, but it’s not impossible. It would just take quite a lot of effort when stalking via binoculars is much easier.
It’s also still possible to clone RFIDs – passports with RFIDs in them could be an especially large problem for both the original holder and the government of that country. The obvious option, credit cards, are still cloneable too, although with modern banking it’s often not worth the investment for the scammers.
However. With tech improving every day, it may be possible to limit what chips respond to which scanners, which would make it much more difficult to invade privacy. Chips get smaller and smaller every day, so it’s entirely possible a password- or signal- protected RFID may some day come into power.
Sources:
https://www.atlasrfidstore.com/rfid-insider/active-rfid-vs-passive-rfid
https://electronics.howstuffworks.com/gadgets/high-tech-gadgets/rfid.htm
https://www.creditkarma.com/credit-cards/i/how-emv-credit-card-chip-works