If you’ve purchased anything online, chances are you’re familiar with CSC numbers even if you’ve never heard the term. After requesting your name, credit card number and expiration date, most online retailers require a Card Security Code (CSC) to complete a transaction.
Used for verification purposes, these three- to four-digit codes serve as virtual PINs designed to prevent card-not-present fraud. While Personal Identification Numbers (PINs) are used to protect and verify credit and debit card numbers during ATM transactions and in-person purchases, CSC numbers are designed to protect cards from fraud during online transactions and other situations where the physical card is not available.