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.
Different 4-digit numbers for each card that can’t be forgotten and don’t need to be written down anywhere.
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:
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).
OK, I quite like that last, I’ll go with that. I’ve got two other cards, let’s see what their numbers are:
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…