Python client for the $20 Colmi R02 smart ring

Is there a similar ring with NFC?

I have no use for the smart health thingies, which really look like a data driven health gimmicks to me.

NFC on the other hand I could find hundreds of applications, from payment to access and transport cards.

The problem with that idea is that all secure implementations of RFID lock the user out, meaning you can't just buy an NFC ring/fob/implant and copy your bank card or transit card onto it. The only implementations where the user can do that are terribly insecure and, while still commonly used, are slowly getting phased out.

So for anything other than systems you control or are good friends with the IT guy for, you're out of luck.

Right I agree with you on theory. But in practice, I already do clone most of my smart cards on small NFC stickers on the back of my phone case.

The things is 99.9% of access cards (where I leave at least) are default-encrypted mifare classic, making cloning trivial. Transport cards are an other beast since they have their own backlog and proper encryption, but there are ways.

So all in all, dumping the card is not the issue for me, it's the medium on which to put the clones that is still a question mark.

The "NFC sticker on the back of the phone" is cool because it's almost as if your phone opens the door (stock android won't let me easily swap NFC SC ID), but NFC is fidgety when multiple chips are in close proximity, leading to frequent misses.

I have found multi-chips NFC cards on Ali Express. These are basically a single antenna wired to an array of chips directed by a keypad. That seems viable on paper but you still get to carry the card and press the right switch.

The ideal solution would be a smart ring with a reflashable NFC chip, along with a programmable MCU to implement the rolling logic between cards.