<Li> "CID": "Card Id", "Card Identification Number", or "Card Identification Code"--Discover, American Express (four digits on front of card) </Li> <Li> "CSC" or "Card Security Code"--debit cards, American Express (three digits on back of card) </Li> <Li> "CVC2" or "Card Validation Code"--MasterCard </Li> <Li> "CVD" or "Card Verification Data"--Discover, sometimes used as the common acronym for this kind of code </Li>

Where is the 3 digit security code visa