Why You Should Change Your Debit Card PIN

ATM Security

If a new study by the Cambridge University Computer Laboratory is correct, most of your Debit (ATM) card PINs are either 1234 or 1111

You may think it’s alright because someone would need to have access to your card to use the PIN, right? NO! Here’s why you should change your PIN right away.

The Cambridge University study confirms that most pick terrible PINs and passwords, especially when they’re things we have to remember, and when we have limited options like “four digits only.” The study also found that we don’t keep our PINs private either, and that nearly half of the people who participated admitted to sharing their PINs with others, and a third of them used the same PIN for all of their cards, which is the same password for all of the web sites you log into. Others thought they were more safe because they used their birthdate as their PIN, overlooking the fact that if they lost their wallet, they would lose their ID card or other card with their birthdate printed on it. This would be a great clue for the finder to correctly guess the PIN.

So whether you’re using a universal PIN, using your birthdate, writing the PIN down and keeping it in your wallet, or giving out your PIN to others, you can see why you need to change it. Even if you know how to keep physical control over your wallet and your ATM and credit cards, the chances of you losing your wallet or getting robbed is higher than someone breaking into your computer and take all of your passwords.

How to Remember Your New PIN

Spell out a word with your PIN
Use a site like Phone Spell to find out what words your PIN spells on a phone or ATM keypad. Alternatively, if you’re still trying to come up with a PIN, type in a word that’s easy for you to remember, and the site will give you a PIN from the numbers each letter corresponds to on a numpad.

Make a sentence from your PIN
Mind Your Decisions suggests you pick a random series of numbers, and then take the first letters of each word for each number, and then build a mnemonic around those letters. For example, if my PIN is 5642, the words are “Five, Six, Four, Two.” I take the FSFT first letters, and come up with a sentence to help me remember, like “First Standing, First Toppled” to lead me back to the PIN. That way any random series of numbers is suddenly easy to remember.

“Encrypt” your PIN in your phone, or on paper
Most banks will tell you never to write your PIN down, and especially not to keep your PIN somewhere it could be lost with your ATM or credit card. Mind Your Decisions also notes that you can “encrypt” your PIN by injecting useless numbers and then writing it down. For example, if my PIN is 1988, I could jot down 01090808 on an index card and keep it in my wallet. That’s easy to guess, so to make it more difficult, I could use the numbers next to the ones in my PIN, like 11928088, or another four digits, where only I know that every other digit is meaningless. Take it a step further and add your PIN as a contact in your mobile phone, complete with this “encryption,” and you’ll never forget your PIN again. It’s not bulletproof, but if you’re the type who needs to write down your PIN anyway, it’s better than no obscurity.

Pick a number that means something to you but nothing to others
If you have a private, personal series of numbers that you can remember and cannot be easily tied to some other readily available information about you then go for it. You’re still stuck with four digits, so if they’re four digits you’ll remember but no one will guess, you’re all set. If it’s something like your dog’s birthday, the last four digits of your best friend’s call phone number, or any other series of digits highly unlikely to be in your wallet and equally unlikely information to be easily available to a thief, it’s fair game.

Use Maths to Memorize your PIN
Another, more advanced suggestion is to useModular Arithmetic to secure your PIN. Here’s how it works: you know how difficult it is to fool yourself into getting up earlier because you set your clock back 5 minutes? You’ll always look at the clock and know to subtract 5 minutes to get the real time, right? The same principle applies to your PIN. Take a random PIN, like 5642, and then add 5 to each digit: 101197. It’s a simple code, but it works, and the key is in your head.

Get the bank to reset your PIN
If doesn’t preclude any of the tips above, but one way to make sure your PIN is a random series of digits is to make the bank reset it, mail you the new PIN, and then force yourself to use whatever they assign you. You can use the mnemonic trick to make it easier to remember, or you can just brute force the number into memory and call it a day. Painful, but it works.

In the end, the method you use to remember your PIN is best decided by how likely you are to embrace the technique and eventually remember the numbers without having to write them down or fall back on something that’s easily guessed or otherwise obtained. Regardless of what you choose, if your PIN is “1111” or “1234” or even some variation on the theme, pick a new PIN, for your bank account’s sake.



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