How I implanted RFID into my hand, and then NFC. Part 1

I always liked the idea of a key that is impossible to forget. And if at the same time the key also fits standard locks - doubly perfect.

Therefore, as soon as it became possible to place an RFID under my own skin that is compatible with anything commonly used, I did this by implanting the EM4100 tag — many cheap locks and access control systems use it.
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And when the NFC compatible tag was discovered - and capable of being the key to laptops, smartphones and the remaining locks - there was absolutely no reason to avoid embedding it.

ATTENTION! This publication is not an instruction, recommendation, guide to action and is intended for reference only. Repeating the following can be fatal or lead to complications and injuries. The author does not recommend performing the described actions on himself and is not responsible for any consequences caused by reading the publication.

RFID

RFID - Radio Frequency IDentification - technologies for the wireless identification of users and equipment. There are a large number of completely different technologies that differ in the operating frequency (868 MHz, 13.56 MHz, 125 kHz, etc.), coding, read-write or read-only, range, battery availability, and purpose.

The reader, the reader , the active tag reader, sends regular requests in the form of electromagnetic waves into the surrounding space. It can be autonomous with its own memory and the ability to immediately control, for example, a lock; or transfer data via RS-485, USB or other means.

A tag, key, tag, tag is a device containing a unique identifier, and, sometimes, a data area. There may be built-in encryption, code execution, other features. Most often it does not contain batteries and is powered by EM waves emitted by the reader.

EM4100 standard

The standard for contactless radio frequency identification cards from EM Microelectronic-Marin. Work at a frequency of 125 kHz.

They have a unique number with a length of 40 bits, which are transmitted cyclically along with the service bytes in an open form. There is no encryption and storage of user data, as well as recording capabilities (officially, unofficially, there have long been discs of cards where you can write an arbitrary number). Obviously, for serious protection at least something does not fit perfectly. However, it is quite widely used in simple SKD, intercoms instead of Dallas tablets, cheap electromagnetic lock controllers and the like. Keys may look like a plastic key chain, a flexible or hard plastic card, or in a different way.

For example, a lock controller with a keyboard and a dozen keys to it for $ 10.

EM4100 Implantable Tags

Basic requirements for an implantable device:

Small size to stay under the skin
Streamlined shape so as not to damage the skin from the inside
Bioinert material - pure silicone, glass
Tightness, strength and sterilization resistance

RFID tags are well suited for implantation, as they do not require replaceable or rechargeable power supplies, contacts, connectors. In 2011, for some reason, it was quite difficult to find labels that are suitable for implantation and, at the same time, are compatible with something widely used. Either EM4100 tags were sold in the form of key chains, cards, cheap and of huge size, or implantable tags to account for animals, which can only be considered a special reader. EM4100 or compatible in a glass capsule - was not.

But it turned out not so bad! On requests for em4100 glass, em4102 glass, rfid glass, we managed to find something similar to eBay and order it right away. Two sets of tags came here, such (left photo - mine, right - rss-systems.de):

First I got the ones on the left, and I was upset about their size. They turned out to be larger than in the photo, and not from glass and not completely rounded. Fortunately, others came behind them, turned out to be glass smooth capsules about 12 mm long and 3 mm in diameter. They were decided to implant.

The process of implantation of the label under the skin

For a while, it took the search for a person who was ready to take up the implantation. In principle, I was ready to do it myself, if there is no one, or to entrust to a friend, a veterinarian, but everything turned out to be easier. A familiar doctor (by specialty - a general practitioner, but, like all doctors, of course, who knows how to put stitches, make subcutaneous anesthesia and cuts) agreed to do everything in the best possible way, and in the summer of 2013 we purchased the necessary materials (Novocain, antiseptics, several medical instruments, sterile scalpels and thread needles) and set about.

Here is what we did:

Sterilization of tags. Since the labels came not sterile, it was necessary to sterilize them. For this, the label was thoroughly washed, then for an hour the label was kept in iodine solution, immediately before being placed under the skin, washed first with alcohol, then with sterile water for injection.
Sterilization tools. Scalpels, gloves, sets of needles and threads were already sterile (and disposable), but the steel tweezers and scapula needed to create a space under the mark in the subcutaneous tissue, required sterilization. There was no access to the autoclave, so I had to use a chemical sterilization method. We used "pyrzhavel" in high concentration. This badly affects the tools (it causes corrosion even of stainless surgical steel), but it is available and works quite well.
Anesthesia. Infiltration anesthesia with novocaine - inject novocaine 20 mg / ml solution subcutaneously into the intended incision site and wait for 5-10 minutes to penetrate into the surrounding tissues. Be careful with Novocain - if you have allergies and / or crooked hands, it can cause many of the most unpleasant consequences, even death! Do not do it yourself if you are not a doctor.
Selecting the location of the label. Usually, small objects are implanted into the space between the thumb and forefinger of the hand (approximately where the mark on the KDPV is located) - the least chance of damaging it when working with something. For the same reasons, the left hand was chosen.
Cut and placement tags. The skin was rubbed with alcohol three times. The incision was made a normal disposable scalpel, approximately 5 mm in length, after having pulled the skin. Since a “bubble” from novocaine solution is already under the incision site, it is quite simple not to be mistaken with the depth. Then, with a dental scapula (a scapula 5 millimeters wide, 30 long and on the handle), the skin was separated from the fiber and the mark was inserted into it with tweezers. In order not to squeeze it back, the label should be at a distance of 1-2 cm from the incision, and not just next to it.
Completion. Since the incision was small, there was no point in stitching it up; we limited ourselves to treating the wound with hydrogen peroxide and applying a sterile patch. I also ingested a dose of a broad-spectrum antibiotic to reduce the likelihood of inflammation, if something still could not be sterilized sufficiently well.

Healing took place without any problems, large tumors, hematomas, inflammations. For three days I drank an antibiotic and changed the plaster, washing the cut site with chlorhexidine, then took it off. The label was felt under the skin, did not cause any discomfort, and - most importantly - it worked!

This is how the cut looked like on the second day

A year later, I added to the existing EM4100 tag a second one, NFC-compatible, which can be read by a smartphone and generally used a lot like. I will talk about this in the second part of the article (if it is of interest, of course).

What it looks like now

If you do not stretch the skin specifically, it is difficult to notice the labels:

There were no problems or complications, including when working with hands, falling or other dangerous actions.

What to use?

I use this label for the same thing I wanted as an electronic key to my room, to the office. The reliability of the standard itself is low, but, as a rule, the electromagnetic lock is not the main one, but only an auxiliary one. In our office, for example, it is used during the day, and at night, when everyone leaves, the door is locked with a mechanical key and the room is armed. So EM4100 is quite enough.

The process of opening the lock (you need to keep your hand back to the reader, since the range is quite small):

Access to the apartment, room, car, office space. A simple confirmation of any action. For serious security, this label is not particularly suitable (see above), but NFC-compatible is less suitable, about it in the second part.

Observations and observations

Labels are not felt in any way, do not interfere with the work by hand, for almost two years nothing has broken.
In metal detectors nothing beeps.
To have the key to the door is always with you, especially from slamming - really convenient.
Reading distance - less than a centimeter, most often it should be skin contact. Therefore, making a copy of the EM4100 is no more difficult than making a copy of a card that is in your pocket. Normal NFC (ISO 14443) is not copied at all + inside cryptography.
No, I have never been bothered by a unique identifier in the body. In the body, and so full of unique identifiers, even more we carry with us in the form of technology and documents.
KDPV not mine, is taken from here , the rights to it belong to its author.

Conclusion and the second part

The experience in implementing the first tag was quite successful, and a year later I decided to expand the functionality with an NFC tag that is compatible, including with smartphones and allowing them to unlock.

In the second part of the article I want to talk about these tags, the ability to unlock the phone or enter Windows using a tag, as well as about another, easier way to implant with a syringe.