Static Data Authentication( SDA) and Dynamic Data Authentication( DDA) are used exclusively to authenticate the card and the static data contained on the card. The CDA procedure is different. This is an extremely secure procedure that protects against cloning, skimming and man-in-the-middle attacks.
In the CDA process, the identity of the cardholder is verified during the transaction using a card verification process. This involveschecking certain personal identification numbers and possibly the signature. A transaction can only take place once the approval process has been completed.