Stripe Snoop

By Deane Barker on August 14, 2004

Why use Stripe Snoop?: This is from a SourceForge project for Stripe Snoop, a mag stripe reader that shows you what information is on the magnetic area of the ubiquitous cards in your wallet. A little scary.

Open your wallet. How many cards in there have magstripes on them? Three? Four? Five? Ever wonder what was encoded on them?

I know I did. I had six cards in my wallet with magstripes. One day a friend of mine had a $200 Magstripe reader, so I ran my cards through. Aside from the expected credit card numbers, I was surprised by the amount of personal information encoded on them. In fact, for reasons I still don’t know, 2 cards contained my social security number.




  1. Since very few of us have access to a card reader, I wonder if you can request (or demand) the issuer to inform you of what is written on the card. And if you find data on the card that you would rather not have there, can you have the card reissued without it? Or better yet, is there a Magstripe reader/writer through which you could do it on your own?

  2. I’m sure you can request it. I work for a company that sells credit cards, and I don’t think you’ll get much in the way of results. And given that the cards are issued en masse, card issuers aren’t really able to change the stripe format for one card and reissue it. You can complain, and threaten to close the card. I’m sure we’d offer to reduce your payments, give you free stuff, etc, but we wouldn’t (couldn’t) re-encode your mag stripe. If you still closed your account, you’d just wind up with another company that has the same problem. Most credit cards in the US are encoded by one of only three companies, so if one card has the problem, it’s likely that around 30% of the cards in the country have the same problem. As an issuer, we can’t change much with what goes on the mag stripe.

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