McDonald's don't your bank does know you authorized an transaction using pin/card/app.
The payment terminal is essentially not actually talking directly to the POS except to tell it that transaction id "xyz"(which only your bank/"card issuer" know is you) was approved, everything else is encrypted between terminal and payment processor and not supposed to be visible to the retailer.
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So how do they know it was me who sent the money and not some McDonalds money launderer ?
McDonald's don't your bank does know you authorized an transaction using pin/card/app.
The payment terminal is essentially not actually talking directly to the POS except to tell it that transaction id "xyz"(which only your bank/"card issuer" know is you) was approved, everything else is encrypted between terminal and payment processor and not supposed to be visible to the retailer.