[xaduha]

NFC tags aka MIFARE Classic and the like? Those would be susceptible to cloning with something like Chameleon Tiny and to repeater attacks. You need actual contactless smartcard support if you want to use it for something serious. Otherwise be ready for LockPickingLawyer making an example of you of how not to do it, he already has similar videos about it.

PC/SC compatible stuff is out there if you know where to look (not affiliated with them) https://webshop.d-logic.net/products/nfc-rfid-reader-writer/...

(ignore the cards they include with the order, proper contactless smartcards or something like an OMNI ring https://store.nfcring.com/products/omni need to be purchased separately)

[mmackh]

Both Ultralight EV1 and NTag 21X are supported and recommended. Cloning is possible for the NTag, but there’s currently no chip out there that can actually lock block 0, which makes detecting and bricking them trivial.

One can make this system as secure as the specs require it to be: brick clones, reject certain tag types, add encryption, add counters, perform analysis server side, etc.

[xaduha]

As long as people are warned it's up to them to decide. Personally I like standards and this on the other hand is a bit of a lipstick on a pig situation. It was allowed to go on for far too long already with every vendor just glossing it over, not unlike what happens with actual locks and keys.