A New Specification Enables a Fast Dip for EMV and Speeds EMV Certification. Here’s How. - PaymentsJournal

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1. The terminal sends a random number to the EMV chip along with the total dollar value of the transaction, if it is known. The trick here is that the total value is often unknown so early in the checkout process. So to enable the chip card to be removed from the point-of-sale (POS) terminal, the POS provides the chip a “predetermined amount” for that merchant, which is typically the same value for all payment networks. The EMV chip, using the predetermined amount, encrypts the authorization request using its crypto key and delivers this ARQC message to the POS.

2. The POS holds on to that ARQC message and indicates to the EMV chip that this transaction will be conducted as a “deferred authorization.” The EMV chip card can now be removed from the POS. The POS terminal retains the ARQC message until the checkout process has determined the total dollar value of the transaction. At that time the POS constructs an authorization message that includes the ARQC crypto-encoded message (added to Field 55), the final correct dollar value into the non-chip data field (Field 4), as well as all other required data elements. This message is sent to the issuing bank.

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A New Specification Enables a Fast Dip for EMV and Speeds EMV Certification. Here’s How. - PaymentsJournal

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