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    Last 4 numbers on a debit card

    This has bugged me someone will know the answer.

    Why is it the long number on a debit card the bank only change the last 4 numbers, yet that's the only numbers printed on a receipt.

    8 Comments

    If they printed the first four numbers, then you wouldn't be able to identify which card you were using. Because as you say they are the same. I think that is the purpose of printing them on a receipt.

    From a security point of view, I have no idea! It winds me up too. Because of things like this:

    wired.com/201…ng/

    first 4 I'd the type like visa or Mastercard and credit or debit the rest I'd the account the last 4 aren't unique so r shown

    The 1st 6 are known as the BIN, that tells the terminal which bank to route the transaction to, the next 9 digits are the unique account identifier and the last digit is a check sum to make sure the card number is correct.

    You can't calculate the full card number from just the last 4 digits and these digits are most likely to be unique.

    Original Poster

    Thanks for the answers,

    dcx_badass

    My last mastercard was identical except the dates and cvv, was weird as … My last mastercard was identical except the dates and cvv, was weird as I've never not had different last four digits on a new card before.


    2 ways of doing it. Either digit 15 increases by 1 which also means character 16 also changes.
    Or, the bank reuses the same PAN (card number) but increments a chip tag called the pan sequence number and the cvv on the rear of the card then changes.
    All depends how the banks systems are setup.
    Edited by: "paul1005" 14th Sep 2016

    Paul1005 spot on with the answer . The first six are the bin and that identifies the bank and the type of card . It's the rest of these number which is unique to your account . The cvv on my current debit card is 000 which raises a few eyebrows . Not telling you the other 16 digits though

    i think the last 4 are printed to help you identify which card was used for that transaction. they need something - if you got home from a night out with 2 CCs and a debit card and 6 bar receipts, you will soon know which cards took a hammering! as has been said, the early numbers are like area codes - common to certain banks/card types (e.g. sometimes I type in the digits and it soon knows it's a master card CC for example)

    https://en.wikipedia.org/wiki/Payment_card_number

    this is the easy bit.
    I still can't get my head around those card readers you need to sign/respond to sign in/add payee to OLB. what the how do they work?!?!?! (have read an explanation and still don't fully get it)

    I think my replacement cards (mainly replaced from wear and tear rather than expiry) have been identical numbers, just expiry and CVV changes.

    Standi

    \x09\x09\x09\x09\x09\x09This has bugged me someone will know the answer. … \x09\x09\x09\x09\x09\x09This has bugged me someone will know the answer. Why is it the long number on a debit card the bank only change the last 4 numbers, yet that's the only numbers printed on a receipt.\x09\x09\x09\x09\x09

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