**Understanding Contactless Payments: RFID and NFC Explained**

As contactless payments become increasingly common, it's essential to understand the technologies behind them. In this article, we'll delve into the world of Radio Frequency Identification (RFID) and Near Field Communication (NFC), exploring how they work and their safety implications.

**What are Contactless Payments?**

Contactless payments allow individuals to make transactions without using cash or a physical card reader. For example, Google Pay enables users to pay for goods and services by simply holding their device near a payment terminal. Even the author of this article uses contactless payment methods with their Girocard, which only requires a few seconds to authenticate.

**RFID: The Technology Behind Contactless Payments**

RFID is a technology that uses wireless communication to identify and track objects. It operates on specific frequencies, including 13.56 MHz (HF) and 125 KHz (LF). The RFID reader uses an antenna to create a magnetic field around the coil, which powers the tag's IC. This is known as Wireless Energy Transfer.

**How Does RFID Work?**

When an RFID tag enters the magnetic field of the reader, it uses a voltage generated by the reader to power its IC. The tag's IC then communicates with the reader using a build-in transistor to short-circuit its coil. This creates slight changes in the amplitude of the sine wave, allowing the reader to receive data from the tag.

**NFC: A Type of RFID**

NFC is a type of RFID that operates on high frequencies (13.56 MHz). It's used for contactless payments and requires a distance of a few centimeters between the reader and the tag. NFC also allows devices to exchange more complex data, such as Android Beam or S Beam.

**Using an Arduino RFID Reader**

The author experimented with using an Arduino RFID reader to read data from their Girocard. Although they were unable to successfully read any data, they demonstrated how to use the reader to write new data to the tag and even use a part of the text data as an identification password.

**How Easy is it to Read Data from My Girocard?**

The author tried various methods to read data from their Girocard using different RFID boards (RC522 and PN532). However, they were unable to successfully read any data. It wasn't until they used a smartphone with NFC functionality that they were able to scan the tag and read its memory.

**Conclusion**

Contactless payments are not as dangerous as most people might think. The use of encryption, shared keys, and close proximity to prevent unauthorized access makes it difficult for attackers to compromise these systems. If you're concerned about security, consider using an anti-skimming card holder for added protection.

The author hopes that this article has provided a better understanding of RFID and NFC technologies and their applications in contactless payments.

WEBVTTKind: captionsLanguage: enNowadays, it is becoming more and more common to use a servicelike for example Google Pay to... like the name impliesPay for something in a store without using cash.Even I use a contactless payment methodswith my Girocard.Which I only have to hold in front of card readerin a store for a couple of seconds to make a payments.But, of course when it comes to money,there will always be safety concerns.So, in this videoLet's learn a bit about RFID and NFCwhich are the technologies used for contactless payments.And at the endLet's determinehow safe this payment methods truly is?And whether it makes sense to use the RFIDand NFC technology in our own simple Arduino projects.LET'SGET STARTED!This video is sponsored by JLCPCBwho manufacture 10 PCBswith dimensions of up to 10 × 10 centimetersfor just $2!Their boards of a good qualityand feature 24-hour fast turnarounds.And best of all,their batch PCBs are cheaperthan from most other PCB companies.When we search for “RFID Reader Arduino” on eBayWe get quite a big selection of boards to choose from.But they boil down to three popular ICs.Those are the RDM6300, PN532, and RC522.To not miss out on anything.I ordered all three of themwhich luckily all came with either an RFID tag or card.But how do we use them?To find that out, I hooked up the RC522 boardto Arduino UNO development boards.According to the wiring scheme,which was presented in the dump in full sketchof the RC522 Arduino library.As soon as the connections were establishedand the example code was uploaded.I opened up the serial monitor.Who after bringing the tag close to the boardssped out a whole lot of information.But why did that happen?And what does the information mean?Well, RFID stands for “Radio Frequency IDentification”which means it has to do with wireless communication.When we have a closer look at the PCB of the readerwe can see that the features an antennawhich we can draw simplified as a coil.Now, the reader IC in combinationwith some passive componentspushes a sinusoidal current through the antennawhich therefore creates a magnetic fieldsaround the coil.The most-used frequencies are either 13.56 MHz (HF)(HF - High Fequency)The most-used frequencies are either 13.56 MHz (HF)which the PN532 or the RC522 used.And 125 KHz (LF)(LF - Low Fequency)And 125 KHz (LF)which RDM6300 used.The tag guts which we can clearly observein this transparent housingconsists of an antenna or coil as welland a small chip.Which, for example can be the Mifare Classic 1K (NXP).(Or it can be NXP iCode SLI)Which, for example can be the Mifare Classic 1K (NXP).When the tag coil enters the magnetic field of the readerit uses a voltage into itand thus also occurrence which powers the IC.This is called “Wireless Energy Transfer”.And if you have never heard of itI recommend you to watch my wireless charging videoas well as my DIY wireless energy transfer system video.Now the tags IC is poweredand as we can see in its datasheetholds 1 KB of datathat it wants to tell us, But how?To find that out, I formed the loopwith my oscilloscope probes ground wireand had a closer look at the magnetic fieldsof the reader.As you can see here.It truly uses a frequency of 13.56 MHzand we can also observethat the amplitude of the sine wave changes quite a bitwhile the reader and tagcommunicates with one and otherThe reason is,that as soon as the tag IC is properly poweredIt uses a build-in transistor to short its coilaccording to the data it wants to send over.This short circuits secondary currentstemps the carrier wave currentsand thus can be observed as slight changesin the amplitudes.And that is how the RFID tag talks with the reader.I will not go into detail thoughwhat the exact steps of the data exchange are.Since there are plenty of tutorials out therethat cover this.And we do not want to get too technical.What is important is that as soon as a RFID tag gets too close to a RFID readerit will spit out all of its information.Which means it is pretty dumb.But more about that later.Because contactless payments does not use RFID,But instead NFCwhich stands for “Near Field Communication“.Only problem is that NFC is a type of RFID.Only difference is that we got more standardized rulesstated in for example, ISO 14443, ISO 18092, ISO 21481(also, ISO 15693)stated in for example, ISO 14443, ISO 18092, ISO 21481Most Importantly though. We only use high FrequencySo, a distance of a couple of centimetersbetween reader and tag is mandatory.And you can also use a reader as a tagto exchange more complex data.(Android Beam, S Beam, etc.)to exchange more complex data.But let's take a quick break from NFCand let's go back to the Arduino example.We can use the readerto also write new data to the RFID tag.And of course use a part of the text dataas an identification password too.For example, light up a LEDThat means such an Arduino RFID readerand tag is great for projectswhere you need permission for something to happen.Which I will keep in mind for future projects.Okay, quick break over...So let's ask the question:How easy it actually isto read the data from my Girocard?No matter whatI tried or what kind of code I utilized theThe RC522 not recognized my card.And by utilizing the PN532 boardwhich can handle more kinds of RFID tags.I was also not capable of reading any data.But that does not mean that there is no way to do that.Because every modern smartphone nowadayscomes with NFC functionality.By installing the “NFC Tools” app(SubMaker: I also recomment NXP TagInfo)By installing the “NFC Tools” appwe can for starters scan the previously use tagto see some general information.But also read out its entire memory.Now, this time my Girocard got recognized.And apparently it is an ISO 14443-4 compliant tag.But while trying to read its memorythe app said that this type is not supported yet.The reason is probably that while it is truethat RFID tags will send out that data pretty carelessly.That does not mean that it is not encrypted.By for example, a shared key.Combine that with the effects letter close proximity is mandatoryand you mostly got a payment limitsContactless payment is not as dangerousas most people might think.And if you want to be super safeYou can always get yourselfan anti skimming card holder for a couple of bucks.It's metal material jams the radio frequenciesand thus let circuits not interact with an RFID reader.And with that being said,RFID is an important technology.Which, for example allows me to own a cardthat opens my youtube channelif I bring it close to my smartphone.I hope you enjoyed this videoand learned a thing or two.If so, don't forget to like share and subscribe.STAYCREATIVEAND I'LLSEE YOUNEXT TIME!(Subtitle : PolaX3)NEXT TIME!