Proxmark3 community

MaxMaker

Contributor

Registered: 2019-07-02

Posts: 2

Can I use a Proxmark to teach a whole batch of tags to a reader?

Hi all, I just ordered a Proxmark 3,

I would like to add an RFID access control system to my rowing club. I have about 500 tags and seven readers. To teach the tag to the readers, you have to swipe them one after another. That is doable now, but in a year or so when the first reader breaks down, how can I re-learn them to a new controller? I won’t have access to the 500 tags anymore.  Since a Proxmark can simulate any tag, could it simulate a whole bunch of tags in a row? Like a batch simulation? That way it could act like a backup and the reader thinks I am actually swiping the tags.

I have a Mifare reader and I use an SBoard Mini as a access controller. At least that is the plan. This is the only system that I could come up with that doesn’t require expensive locks or software.

mwalker

Moderator

Registered: 2019-05-11

Posts: 318

Re: Can I use a Proxmark to teach a whole batch of tags to a reader?

I have been thinking about this.  this is just a theory (not tested).
To re-cap/assumptions
You have X readers and 500 tags
Each reader is 100% independent from each other.  i.e. no central store/management.
To allow a tag to work at a reader, you need to present the tag to that reader.  So to program X readers, you need to present 500 tags to all X readers (one at a time).

Issue: When a reader is replaced, no-one can access that door until the tag as been added.

If the reader is just using the UID or the UID and a common block then in theory you should be able to store that list and script this.
e.g.

Load emu : hf mf eload <basic "card">
for each UID in list 
   hf mf sim u <UID> n 1

where n 1 is exit after 1 read, may need to tinker with this
If there is other unique data needed, then you could also save that and load that for each UID via the hf mf eset command

Note: you will need to ensure the "master file" is kept safe and secure, if leaked out you could have to re-issue all tokens.
While this is not a recommendation for your setup, just a rely to your question,  I think you also need to consider how you revoke access.  e.g. Lost tag, member leaves etc.