Working on it. What's a "card security code"?
On the back of your card, near the signature there should be three numbers in small print. That's your security code.
Your credit card has a security code on it --- if it's American Express, it's a 4-digit code on the front upper right corner; if it's Visa, MasterCard, or Discover, the code is three digits and on the back right above the signature strip.