I have a bit of a unique application. I'm trying to create fancy ID cards for local membership.

It's a cocktail club, and they're doing some cool things with the front of house and service structuring. All that to say, they want to use some nice brass magstripe cards for members IDs, but they'd like to further integrate them into their POS, which is currently Square for Restaurants.

I've talked to them about RFID, and about magstripes, but I'm further not entirely familiar myself with what the POS system looks at from a credit card stripe, which stripe the data lives on, how it's encoded past the reader, etc.

I've got a reader/encoder that I can use to read data, but I'm not seeing consistency between the selection of cards I have in front of me. I have some work to do on the interpreting side, I suppose. Does anyone have experience encoding data on a magstripe specifically for use by a POS system? I'm only trying to create a card that mimics the functionality of a credit card for ID purposes, so not for payment, and I'm not trying to take part of the credit card magstripe data from another real credit card to then repurpose on a created ID card for ID. These cards are totally separate from real credit cards, but use the magstripe out of convenience.

  • 1
    Can you please rephrase your question? I don't really know what exactly you are asking. – MechMK1 Sep 13 '19 at 7:26
  • What is your question? It sounds like you are trying to use your custom cards in a POS machine that is designed to read credit cards. If you want to make your own credit card, you will need to work with the POS provider to see how you can integrate. But, most likely, you are trying to fit a round peg in a square hole. In short, you need to talk to Square support. – schroeder Sep 13 '19 at 8:39
  • Edited for clarity. Talk to Square.... Ha. Haha. Very funny. "Round peg in a square hole" is my middle name. Good insight into my poorly worded query. Comment edit: I know that this isn't strictly a security issue. The problem I've got is no one else studies magstripes and their security. Effectively, I am trying to bypass the POS security at a level. Further, I'm way more comfortable with RFID data processing, but I don't know of POS systems that use RFID. NFC is different. – R. Taylor Garlock Sep 13 '19 at 14:09

Since you asked in a security forum, mag stripe cards are considered wildly insecure. They’re easily clone-able, which data is easily read and written to. The data on the card is static and pretty much free for all.

However, you might consider a cocktail club a relatively Low-value target, and can generally accept this risk given chip cards are way more expensive to both print and process.

For more details, typically card data is encoded onto the ‘tracks’ of a mag stripe card, with some details here. I’d bet you can buy off the shelf electronics to both process and handle magstripe cards anywhere.

| improve this answer | |
  • Yep, it's a security question because of the tech, but.... believe it or not.... These "ID Cards" won't be used for payment or anything other than ID purposes. Not strictly just a formality, because it will generate a ticket inside the POS like other cards do, but the card won't hold payment details. – R. Taylor Garlock Sep 13 '19 at 14:06

Not the answer you're looking for? Browse other questions tagged or ask your own question.