What Is a Card Security Code (CSC)?
A Card Security Code (CSC) is a short numeric code printed on your credit or debit card that serves as an extra layer of verification during online and phone transactions. You may also know it by other names depending on your card provider:
- CVV – Card Verification Value (Visa)
- CVC – Card Verification Code (Mastercard)
- CID – Card Identification Number (American Express, Discover)
- CSC – Card Security Code (generic industry term)
Despite different names, they all serve the same purpose: proving that the person making a transaction physically has the card in their possession.
Where Is the CSC Located on Your Card?
The location of your security code depends on the card network:
| Card Network | Code Name | Location | Digits |
|---|---|---|---|
| Visa | CVV2 | Back of card, right side of signature strip | 3 |
| Mastercard | CVC2 | Back of card, right side of signature strip | 3 |
| American Express | CID | Front of card, above card number (right side) | 4 |
| Discover | CID | Back of card, right side of signature strip | 3 |
How Does the CSC Protect You?
The CSC provides security in a very specific way. Unlike your card number, the CSC is never stored by merchants after a transaction is complete — this is a strict rule enforced by the Payment Card Industry Data Security Standard (PCI DSS).
This means that even if a retailer suffers a data breach and a criminal obtains your card number, they still cannot complete an online purchase without your CSC. The code is a physical security measure — it proves you have the actual card.
What the CSC Does NOT Protect Against
It's important to understand the limits of your CSC:
- It does not protect you if someone physically steals your card
- It does not help if you enter it on a phishing or fake website
- It does not protect against malware that captures keystrokes
Should You Share Your CSC?
Your CSC should only ever be entered on secure, trusted websites (look for https:// in the URL) or provided verbally to a known, legitimate company. Never share your CSC via email, text message, or social media — no bank or legitimate business will ask for it this way.
Key Takeaways
- The CSC (CVV/CVC) is a 3–4 digit code printed — not embossed — on your card.
- It verifies you physically possess the card during card-not-present transactions.
- Merchants are prohibited from storing it after a transaction.
- Guard it as carefully as you guard your full card number.