The 2 times my CC info was compromised it was traced back to restaurants I’d eaten at. A staff member just copied the information down. That’s often how it happens. I know nobody here wants a math lesson but digital encryption is pretty fascinating stuff. Simple, yet genius in its simplicity and effectiveness.
Funny coincidence! I opened my Facebook this morning and check the “memories” thing. 5 years ago today for a fun number theory exercise I taught my students how credit card numbers are generated and how they could figure out what the missing number was on my credit card without guessing. Sorry, I won’t derail the topic any further.
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