# Credit Card Numbers

**URL:** <https://boards.straightdope.com/t/credit-card-numbers/5007>\
**Category:** Factual Questions\
**Created:** [November 30, 1999, 2:13pm UTC](https://boards.straightdope.com/t/credit-card-numbers/5007 "1999-11-30T14:13:00Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\
**Post date:** [November 30, 1999, 2:13pm UTC](https://boards.straightdope.com/t/credit-card-numbers/5007/1 "1999-11-30T14:13:00Z")

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On two recent over-the-phone credit card purchases, I’ve been asked to read a 3-digit number that appears on the back of the credit card after the account number. (The account number + 3 is printed on the signature tape box.)

Is this a recent addition for security purposes? (The oldest card I have is only 1 1/2 years old.)