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Diagram illustrating SDA, DDA, and CDA offline data authentication methods

Credit Card

What are SDA, DDA, and CDA?

SDA (Static Data Authentication), DDA (Dynamic Data Authentication), and CDA (Combined Dynamic Data Authentication) are offline data authentication methods used in chip cards. Learn how each one validates the card and the transaction.

Diagram showing the EMV chip card static data authentication (SDA) process

EMV

What is a Data Authentication Code (DAC)?

DAC is the abbreviation for Data Authentication Code. It is a piece of data assigned by the issuer and held by the terminal during the Signed Static Application Data verification process.

POS terminal processing an EMV chip card transaction

Credit Card

Application Interchange Profile (AIP)

The Application Interchange Profile indicates the application functions supported by the card. The AIP values and their descriptions are given below. Where is the AIP found? The AIP is a 2-byte piece of data stored on the card, carried under EMV tag 82.

Photo of a POS terminal related to EMV Issuer Action Code settings

Online & Authorization

Issuer Action Code (IAC)

These are codes that communicate the issuer's conditions for approving a transaction online (IAC-Online), for declining it (IAC-Denial), or for declining it when the terminal cannot go online (IAC-Default).

Diagram illustrating the card authorization process

Merchant & POS

What Happens During Authorization?

Today, credit cards play an important role in our daily lives. We can carry out almost all of our transactions without carrying cash, using our credit card instead. During a purchase, we hand our card to the cashier and enter our PIN at the POS terminal.

POS terminal used for EMV card payment processing

Merchant & POS

TVR (Terminal Verification Results)

Terminal Verification Results (TVR): a sequence of bits produced when a terminal reads an EMV card, based on logical checks such as an expired card. This data object is used to decide whether a payment transaction should be accepted online, declined, or allowed to proceed.