Where to start?


So I’m pretty familiar with the idea of the whole NFC chip in your hand thing but I can’t actually think of anything I’d use it for, don’t suppose you guys have any ideas?

I thought maybe scanning my college pass but won’t that be encrypted in some way?

You can rewrite the ‘tag’ too right, you’re not stuck with what’s in it once it’s in there? I’m not going to be at college for ever so I thought I’d ask to make 100% sure as NFC isn’t my expertise

Does anyone have any tips for reading tags to see if there’s any locks on them that would prevent me copying one to VivoKey Spark?

Also is there any optimal position for the implants? I ideally wanted the one that supports Java Applets such as Fidesmo services but I don’t think that is going to fit in the same place as the spark is normally implanted (due to the size of it being greater)

does it get awkward to maneuver your hand to touch readers?



I suggest you start here.

Just to clear up some misconceptons:

There are tons of different kinds of RFID tags. Some have encryption, some don’t, some are clonable, some aren’t. First step to see if you could replace an existing card with an implant is to positively identify the type of card used. Typically this is done with one or more of the following: identifying markings on the original card, scanning the card with tools, scanning the reader with tools.

Cloning is only used where you cannot enroll your tag into the system that you want to use it in. For instance, your school will probably not allow you to go to them and say “I don’t want to use this badge, give my implant access instead”. But in other situations, like you buy a door lock that uses RFID, you can enroll your own tag into it since you control that system. In other situations, you may actually be able to convince the people controlling the system to enroll your tag…

You can’t clone a tag to the Spark. The spark cannot be written to, but contains a cryptographic engine that can be leveraged through various services TBD.

The most common place for an X series implant is in the webbing between the thumb and index finger. But you are right, that location is not optimal for a flex series implant.


To answer a few of your questions, I use my tags for a lot and plan even more. I have an xEM in my right hand I use for getting into work and soon my house. I’m also planning on setting it up in my car so all I have to do is wave my hand on the door and it’ll unlock and give me 30 seconds to start the car. I also have an xNT in my left that I use for storing crypto keys. I’ll eventually move them to more secure storage in another implant later. And it’s not too awkward to hit a reader with your hand as long as you know what the right orientation is. Use the xLED to see the field. On most HID readers you want the tag perpendicular to the edge of the case of the reader.


So for that it’d be more along the lines of similar usage to a Yubikey? Very convenient sounding as I keep forgetting mine…

Would this be one that you could write to? Either RFID things such as bus passes (I’m assuming these are RFID based) and NFC for stuff like links to portfolios or contact detail sharing etc

Are these writable once inside of you also? Also do they last forever? Another VivoKey product I saw had a label called “data retention” with 10 years listed on it - I ideally wouldn’t like to have to be cut and restitched every decade

Thanks again.


Yes the idea of the Spark is similar to a Yubikey. Integrations with various services are in the works, but no details are available yet.

You can write NDEF records (urls, VCARDS, phone numbers) to the xNT or the xNT side of the NExT.
These NTAG216 based tags are not used for anything that requires monetary security like bus passes. Those will use something more secure like the desFIRE chips (among others). SO you would not put your bus pass on it (unless the bus company was really dumb)

The xNT and NExT are writable once installed.

The data retention rating typically refers to a chips ability to retain data in unpowered storage. In other words if you write something to it, and then put it on the shelf and didn’t touch it, the data will still be readable after at least 10 years. If you re-write to it, it will be refreshed and the 10 years starts over. 10 years is a rated minimum. In reality it’s closer to 100 years. Now this is different than the rating of the number of times it can be written to… Non volatile memory has a finite number of writes it can sustain before it wears out. The good news is, this number is usually above 100,000 writes. And again, that’s a minimum number. But if you are writing your tags that much, you have bigger issues… lol.

Specs for the NTAG216