What is an RFID chip, and what does it do?

What is an RFID chip, and what does it do?
Image source: Getty Images

RFID stands for radio-frequency ID. You might not know what an RFID chip is, but you almost certainly own at least one. They’re in everything from pet tags and passports to bank cards and library books. Some people even embed them in their hands rather than carrying a card!

What are RFID chips?

At a practical level, RFID chips are tiny electronic tags. When you scan them with an RFID reader, the tag sends its information from the tag using low-powered radio waves.

Some RFID chips have their own batteries, but most are actually powered by energy from the reader. The ones with batteries can have a range of up to 100 metres, while the passive ones are limited to a few centimetres.

The smallest RFID chips are 0.05 x 0.05mm, the size of a grain of dust. However, most are about the size of a grain of rice or the tip of a match.

Are RFID chips like bar codes?

Yes, but in many ways, they’re even better. RFID chips can store more information, they’re more durable, and you don’t need to be able to actually see them to read them.

From the manufacturer’s perspective, they’re harder to copy. Better, they can be reprogrammed as well as read, and they can be scanned by several readers at the same time.

Where are they used?

A better question is: where aren’t RFID chips used? They’re all over the place. As a general rule, wherever you find bar codes, you’ll also find RFID chips.

Some of the places you’ll come across RFID tags are credit cards, passports, inventory and asset tracking, public transport ‘tap and go’ cards, library books, electronic toll booths, access cards for hotel rooms and businesses, churches, and pet and animal tags. Some scientists even use them to track insects!

More interesting uses are tracking surgical instruments and dressings (to make sure the surgeons don’t accidentally leave them inside you), and tracking competitors in major sports races: if you tag the participants, the computer can detect who crosses the line first!

What blocks RFID chips?

Wood, cardboard and skin don’t block RFID chips, but metal does. You can buy special wallets with built-in RFID shields to block the signal, but wrapping them tin foil works just as well.

Contrary to popular belief, fixed magnets don’t normally affect RFID chips. Changing magnetic fields can power RFID chips, but they can’t block or change them. Be warned: even though magnets don’t affect RFID chips, they can damage the magnetic strip on some cards, so be careful!

One thing that can damage RFID chips, however, is putting them in the microwave (which can also cause a fire and damage the microwave) and hitting them with hammers. If you’re worried about RFID security, you’re much better off with an RFID shielded wallet.

Are they secure?

In some ways, RFID chips are less secure than bar codes. They can be tracked, skimmed, and infected with malware. You can even read them with completely legal smartphone apps.

Speaking of smartphones, RFID tracking is simple and common, but it discloses less information than the smartphone most people carry without a second thought.

When it comes to bank cards, there are several pros and cons to contactless payments. They’re convenient, but bank card skimming is a problem.

There are two types of skimming:

  1. Using an illegal device attached to an ATM; and
  2. Using a dedicated reader that can receive your card details while it’s in your pocket.

The first is fairly common, but you can protect against it by checking ATMs carefully before inserting your card. There are no statistics for the second type, so it’s probably rare. If you’re worried about it, you can use a wallet with an RFID shield to shield the chip.

A bigger problem with contactless bank and credit cards is that if you lose your card, other people can use it. Obviously, the solution is to not lose your card; however, if you do lose it, contact your bank immediately and cancel it!

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