Proxmark3 community

Kurushimi

Contributor

Registered: 2018-04-09

Posts: 6

Can I simulate a 125khz HID RFID card with an Arduino

So, after playing around a bit with an Arduino and an RFID reader from Mikroelektronica (https://www.mikroe.com/rfid-reader-board), I was able to read the ID off of my RFID card, which is a 125 khz HID card. 

But now I'm wondering whether or not it would be easy to simulate an RFID card using my arduino, and maybe an antenna. I'm thinking if  I just hook the antenna up to an arduino pin which I turn off and on in the right pattern it might work the same as an RFID card. Do you think something like this will work? If not, do you think there's anything I can do to properly simulate an RFID card with an Arduino?

iceman

Administrator

Registered: 2013-04-25

Posts: 9,538

Website

Re: Can I simulate a 125khz HID RFID card with an Arduino

you do know that you are posting in a dedicated proxmark forum?

Kurushimi

Contributor

Registered: 2018-04-09

Posts: 6

Re: Can I simulate a 125khz HID RFID card with an Arduino

Sorry, was this question not on topic? I came here because this forum was a big help in the past, since I came across a post with a very detailed and helpful explanation of how the HID card protocols function. So I figured the people here might be knowledgeable about the physics behind RFID cards. So basically I'm wondering how complicated it is to simulate an RFID card and whether it is something simple enough that I could do it with an Arduino.

I see you're an admin. So, do you know a lot about the proxmark? Like, the components that make it able to simulate an RFID card? Do you think it would be possible for an electronics newbie to build the necessary components to simulate an RFID card?

I also googled it and found some method that I think might work, but I figured I may as well ask here too just to see if someone could give me some more insight into the issue.

Anyways, thank you for your time.

Last edited by Kurushimi (2019-08-24 16:35:54)

grauerfuchs

Contributor

Registered: 2018-08-28

Posts: 50

Re: Can I simulate a 125khz HID RFID card with an Arduino

It is off-topic in that it's RFID in general and not related to the use, support, features, and abilities of the Proxmark device.

As for your Proxmark question, the work is primarily shared between the CPU and the FPGA. The FPGA handles the actual signal and the CPU processes it to and from something usable and also handles the computer interface.

I do recall seeing something about a project that allowed an Arduino to sort-of simulate a single card, but it was programmed in very low-level methods using a lot of assembler code. The code was not beginner friendly, and it was locked to that one specific card that it could send. If you want something capable of simulating an arbitrary card that you program or change on the fly, you're going to be disappointed. The Arduino simply doesn't have the ability to handle all of these tasks in the required time (yet). There used to be an RFID shield that would handle the heavy lifting, but even if you could still find one (they have long since been discontinued), the option to simulate any given tag was something well beyond what the shield could do.

If you're a beginner in electronics, electronic theory, and also in RFID technology, you're most likely going to be in well over your head in trying to build something from scratch. The schematics for the Proxmark device are available on this site. I suggest you review them. If you can trace the signal paths and understand what is happening and where, you might be able to build something on your own. If you can't follow the schematic, consider this: The schematic and associated notes provide all the details on how it works without you having to go through and engineer something equivalent from the ground up. The theory behind how it works and the design of electronics are both two big disciplines that usually require a lot of time investment and a lot of learning.

If you honestly want to get into this and fully understand it to the level needed to build a card simulator from scratch, you should start your research on how AM radio works. Then once you understand that, look at FM radio. Once you understand those enough to build a transmitter and a receiver from scratch, start looking into the detailed theory of how antennas work, and also how EM fields are affected by nearby conductive and non-conductive materials.

Once you understand that to the level where you can calculate how much of an energy drop there will be on the transmitting antenna when a resonant antenna with a given load moves into its near field and how you can detect said losses while the transmitter is operating, then you'll be in a good position to figure out the design of a device capable of simulating an RFID card on its most basic levels. From there, it's all a matter of varying how much energy to "steal" from the field and when.

Kurushimi

Contributor

Registered: 2018-04-09

Posts: 6

Re: Can I simulate a 125khz HID RFID card with an Arduino

Oh, I see. Sorry for misunderstanding the topic of this forum.

Yeah, and I agree that you'll need some low-level Arduino programming to get this to work. But I think I can get it to work using interrupts. At least for low-frequency (125 khz) the CPU is fast enough to properly process these signals and using interrupts triggered by voltage changes was fast enough to properly decode the output.

Thanks for your help. Yes, I'll look into AM radio and electrical theory to see if I can understand how this stuff works. Have a nice day.

anybody

Contributor

Registered: 2016-12-20

Posts: 36

Re: Can I simulate a 125khz HID RFID card with an Arduino

Kurushimi, try