NFC R/W Information / Decode

NFC
#1

Hello community,

Newbie here. Is it possible to read and interpret information from a NFC card (not the UID level read), then write something else on it? Is there a way to export this data into a PC to read it in a text editor? Does this operation require knowing the protocol since is a 2 way communication? Are there any workarounds?

For example: An NFC card that is loaded with the text (can be anything really) “AAA”. I want to read the card and get the “AAA” text and load it into a text editor. After that rewrite the text into “BBB”

#2

Hey @Ily,

From what I understand, (but have been unable to test due to not having any rewritable tags around) this is sort of possible. Be careful though, this can open quite the can of worms as far as researching and understanding the protocols. I haven’t worked out any emulation 2 way NFC tags, but the tags that communicate data or cause phones to do things are strictly one way. This is done in the NTAG format where the data or instructions are communicated via pages of hex data. For example, I have attached one that you can emulate to make a phone open YouTube and Rick Roll someone.
Rickroll_no_ads.nfc (3.1 KB)
The .nfc files can be opened in any text editor and modified.

Some more information on making this play whatever video you want can be found here: https://github.com/UberGuidoZ/Flipper/tree/main/NFC/Fun_Files

There is a lot you can do like connecting guests to a WiFi network, but my struggle has been figuring out how to actually write the NFC payloads in Hex. If anyone else has some pointers that would be greatly appreciated!

Now what you can’t do is write an NTAG NFC tag with the Flipper, but you can buy relatively cheap NFC writers on Amazon to use with a computer or even use NFC Tools and your phone. If you don’t want to have to struggle through learning the protocols and writing hex data, you could buy some rewritable NTAG chips and use your phone to write the payloads (since it’s done in a nice little GUI) and then read the chips with your Flipper to emulate.

Let me know if you have any other questions!

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