Card Security Code (CSC)

 Amex Requirements
Card Security Code REQUIRED 4 digit, non-embossed
number printed above your account number on the face
of your card. This number is recorded as an additional
security precaution.
 
Visa Requirements
Card Security Code REQUIRED 3-digit, non-embossed
number printed on the signature panel on the back of the
card immediately following the Visa card account number.
This number is recorded as an additional security
precaution.
 
MasterCard Requirements
Card Security Code REQUIRED 3-digit, non-embossed
number printed on the signature panel on the back of the
card. This number is recorded as an additional security
precaution.
   
Discover Requirements
Card Security Code REQUIRED 3-digit, non-embossed
number printed on the signature panel on the back of the
card. This number is recorded as an additional security
precaution.