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.
Signing up for a PayPal account will be required to complete this purchase.
I don't have a pay pal account, nor do I want one. Is there another way to donate?