Passwords: Pinning down the PINs

Are you any good at remembering numbers? Most people I’ve met say they’re not.

What would you say if I said I had a way of remembering all the PINs on all of my credit and debit cards – a way that doesn’t require me to remember ANY numbers at all?

Short of time? Skip the next four paragraphs…


My Mum can never remember her PIN. She’s got five different cards, each of them has a different PIN. Against all the rules, she has her PINs written down on bits of paper in her purse. Thankfully her little scribbles don’t identify the PINs with the cards – but that just means she has trouble matching up the cards with the PINs. When she’s at a checkout she rarely gets the right one first time. She’s special, my Mum is (she’s my Mum!)… but at the same time I have this sneaky suspicion that her behaviour isn’t that different from most other people.

I’m not my Mum. I don’t have five cards, I only have three at present. I don’t have any problems at all remembering the PINs for each card – but that’s because I’ve disobeyed another cardinal rule where passwords are concerned. The PIN for my three cards has been the same 4-digit number, since ummm… about 1988 (and no, my PIN isn’t ‘1988’ ). I’ve never written my PIN down anywhere… but every single time I enter the number on these new-fangled widgets that are in all the shops these days, I think “it’s about time I did something about this”.

The ‘account number’ on credit cards is actually an ISO 7812 number. Not sure why I mentioned that really, it’s not particularly relevant. Should I just go ahead and delete that link? Nahhh, it gives you somewhere else to go if you’re bored with what I’m saying. Unlike most websites I don’t want your eyeballs (I just want your soul – ah, just kiddin’ ya )… where was I? Oh, yes. According to that Wikipedia link, the maximum length of such a number is 19 digits. All the cards I know of these days bear a 16-digit number.

That reminds me of a trip to France. Paris. A boat on the Seine. It was a restaurant. I was entertaining my biggest client. My Barclaycard had 13 digits. After the meal… the waiter woudn’t accept the card: “But, monsieur, zis card, she ‘as… ‘ow you say? Not enough digits, I cannot agzept ‘er.” Egg, meet face. Shortly afterwards I got a new card with a new 16-digit number and a letter from Barclaycard telling me that the older numbers were being ‘phased out’, or something. Thank you so much, Mr. A. Smeghead at Barclaycard’s Facial Omelette Dept, for revising the merchant systems before telling the lowly punters who pay some of your wages. Smart move. If that had happened in America I would have sued you – but, no, I’m a Brit. In fact I still have, and use, that Barclaycard you sent me… wait, what? Why? Oh, yeah, I remember, it’s coz I’m a Brit.


Required:
Different 4-digit numbers for each card that can’t be forgotten and don’t need to be written down anywhere.

Solution:
Derive the PIN from the account number that’s already printed on the card.

That 16-digit number is embossed right there on the card, in four groups of four. It looks like this:

0123 4567 8912 3456

Four groups of four? I need 4 digits for a PIN…

… so what’s stopping me picking the first four (0123) and using those as my PIN for this card? Those four are as good as any other four I might pick at random – unless of course lots of people already use those four (which according to that ISO standard I mentioned above will be common to a great many cards) and if the credit card thieves know that lots of people use these four then – maybe that’s not such a good idea after all.

So what about the second four? Well, I could use those (4567). Or the third four (8912). Or (you guessed it) the fourth four (3456). Simple.

But we’re on a roll – let’s not stop here. What about picking the first number from each group? (0483). Or the second number from each group (1594), third (2615)… or the fourth from each group, but this time: backwards! (6273).

Last from group 4, first from group 1, last from group 3, first from group 2 (6024).
Third from group 3, first from group 2, second and third from group 4 (1445).

0123 4567 8912 3456

OK, I quite like that last, I’ll go with that. I’ve got two other cards, let’s see what their numbers are:

9876 5432 1098 7654
1111 2222 3333 4444

9565 and 3244.

Best of all, I don’t have to remember any numbers to recall the PINs. All I have to do is visualise where those numbers are in the pattern, and bingo 🙂

I can now go to any hole-in-the-wall cash machine, or any shop with chip-and-PIN, pick any card, look at it, see the PIN, hand the card over, enter the PIN, get the card back, forget the PIN. Sorted.

Well, it will be sorted once I get off my backside and go to a hole-in-the-wall to change the PIN on my cards from the current one-size-fits-all one…

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About pendantry

Phlyarologist (part-time) and pendant. Campaigner for action against anthropogenic global warming (AGW) and injustice in all its forms. Humanist, atheist, notoftenpist. Wannabe poet, writer and astronaut.
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7 Responses to Passwords: Pinning down the PINs

  1. Stuart says:

    It’s an interesting concept, I quite like it. Of course if you’re damn careful with your card you shouldn’t need to worry too much about people figuring out your PIN ;O)
     
    All the best,
    Stu.

    • pendantry says:

      Thanks for your comment, Stuart. However, I think you may have missed the point, which is twofold: (1) this is a way to have different PINs for every card (ie added security) and (2) all you have to remember is a pattern, no numbers.

      Our brains are natively good at pattern-recognition: memorising things (especially numbers) takes practice.

  2. Vicky says:

     
    Colin! How nice! Thank you for your comments. Shame you have to rush off but please do come back and read again. The story goes back about ten earth months in text and before that several more in binary. I hope you have time to read all of it! It is also going forwards of course, a new episode being posted every day, sometimes two episodes as I try to keep some in hand. Occasionally I do get sidetracked (lead astray) and now and again (often) I have to consult a diary or archive of my own (many of the happenings are based on my life anyway) There are two grey cats currently (brothers) which can be troublesome because they need a lot of attention. They live under my bed. My characters Mo and Miny are based on a brother and sister in law I once had and Astie is loosely based on a person in the ladies shoe trade I once knew………Else is just a girlfriend. So there you have it – my alibi.  Interesting what you say about pin numbers. I use some numbers out of my pension book for my pins (2 cards) but never have all three items in the same purse together…….. in an idle moment (few and far between) I am learning (via correspondence course) the common Venusian language (difficult!) So far I have the greeting, a greeting at any rate, which looks something like, when it is written down in English, \’Naj Adar\’  It can mean several things dependig upon where it is placed in the sentence. Sometimes it is used to set the mug of tea down on………                                                                                   Thank you again, I hope to talk to you again soon! X Vicky X 

  3. penelope says:

    Yes Boris is his middle name, but it’s pronounced " Bore is"  because he’s posh don’t you know, what! what!
       Pen

  4. Vicky says:

     
    aaah… now that binary came about when I was having some little difficulty with my antenna array. Some cowboy riggers on the god foresaken planetary stopover (Allanna Theta) I had the misfortune to encounter, used electricians pvc tape on the joints in the coax with the resulting leakage of my signals and the cooking by errant microwaves of a good many of my houseplants. They still owe me for the screned connectors I paid for but which were never used. Next year I shall be returning to Allanna Theta (I think it was) and shall reclaim my money then.  I do hope you found the read enjoyable…….. x Vicky x

  5. Vicky says:

    bloody hell Colin! Did you go back and read everything? No-one has ever done that before to my knowledge anyway!
    So you made today a record for me – 116 page views (so far) by 8pm……………… I am flattered!   XXVickyXX

  6. Pingback: Passwords: storing passwords | Wibble

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