The CSC is a three- or four-digit value printed on the card or signature strip, but not encoded on the magnetic stripe.
- MasterCard, Visa and Discover credit and debit cards have a three-digit card security code. The code is not embossed like the card number, and is always the final group of numbers printed on the back signature panel of the card. New North American MasterCard and Visa cards feature the code in a separate panel to the right of the signature strip. This has been done to prevent overwriting of the numbers by signing the card. The codes have different names:
- "CVC2" (card validation code) MasterCard,
- "CVV2" (card verification value) Visa,
- "CID" (card identification number) Discover.
- American Express cards have a four-digit code printed on the front side of the card above the number. It is printed flat, not embossed like the card number. This code is called:
- "CID" or "unique card code"