Internal process of EMV Debit/Credit Chip Card

Card detection and reset needs to be performed by the card interface functions specific to the hardware device being used. When a card is reset, it will respond with an Answer To Reset (ATR) that specifies how the terminal must interface with the card.
July 26, 2023

Satish Patel

EVM Online Payment Framework


Card Detection and Reset:

The card interface functions particular to the hardware being utilized must be used to execute card detection and reset. A card will answer to a reset request with an Answer To Reset (ATR), which details how the card should be interfaced with by the terminal.

Candidate List Creation:

A candidate list of EMV applications that are supported by both the terminal and card must be generated by the terminal, which has a list of all the Application Identifiers (AID) of EMV apps that it is configured to support. A directory listing of all card applications may be requested by the terminal from the card’s PSE. The terminal must repeatedly ask the card whether it supports each individual AID in its list if this is not supported or if it cannot discover a match.

Application Selection & Read Application Data:

If there are more than one programs within the finished candidate listing, or the utility requires it, then the cardholder may be asked to select an software; otherwise it can be robotically decided on.

Once the utility has been selected, the terminal provides the cardboard with any information that it requests within the PDOL and gets the processing options. The cardboard will supply the application document Locator (AFL), that is used by the terminal to study the application data data from the cardboard. Those information comprise the cardboard PAN and expiry date, plus many different tags of data which can be used for transaction processing which includes cardholder verification and card authentication.

Application Cryptogram:

For the duration of an EMV chip transaction, an utility cryptogram is generated the usage of two- key triple DES cryptography. This is a signature generated from critical data factors contained in either the web authorisation request to the cardboard provider (if online authorisation is needed), or the very last financial transaction required for clearing and agreement.

Application Cryptogram

The cryptogram this is generated for the web authorisation request is called the Authorisation Request Cryptogram (ARQC) and the cryptogram this is generated via signing statistics elements while a chip approves the payment for clearing and agreement is called the Transaction certificates (TC). If the transaction is declined, the chip will generate a cryptogram called an utility Authentication Cryptogram (AAC).

Cardholder Verification Processing:

Cardholder verification tests that the individual using the cardboard is the cardholder. The cardboard carries a Cardholder Verification approach (CVM) listing of verification methods that it supports, and the situations below which they must be carried out. The terminal must navigate thru this list and attempt the primary approach it unearths for which the situation is met. If a way fails, the terminal must test whether or not extra methods are allowed. As an example, a listing may include: on-line PIN (if unattended coins), offline PIN (if supported), signature (constantly).


Risk Management and Authorisation Controls:

EMV chip transactions offer the issuing bank with controls at the factor of sale which enables allow the issuer to lessen exposure to fraud and credit chance for offline and beneath floor limit transactions. The issuing bank can set limits within the chip card that restriction the wide variety of consecutive offline transactions that may be processed.


Additionally, EMV defines script instructions that can be back to the card in a web authorisation reaction that lets in the issuer to change the cardboard limits, possibly even reducing them to 0 depending upon assessed danger profiles. Issuers may also issue scripts to block or disable a lost or stolen card.

Processing Restrictions :

Processing restrictions allow the terminal to determine the compatibility of the packages on the cardboard and terminal. This includes checking if their application version Numbers match, if the card application is expired or pre-legitimate, and whether or not the utility usage control (AUC) allows the present day transaction to be completed.

Terminal Action & Card Action Analysis:

The terminal will examine the results of the previous verification, authentication and danger steps and this could bring about the terminal informing the cardboard that it proposes to both are trying to find on line authorization of the transaction, or to complete it offline by accepting or declining the transaction locally.

During the primary Card action evaluation step, the cardboard will analyze the results of all the previous steps and this could result in the card asking for the terminal to both are trying to find on line authorization of the transaction, or to complete it offline by using accepting or declining the transaction regionally. This request may also fluctuate from the motion that the terminal proposed following Terminal motion evaluation, but is challenge to sure common sense policies (e.G. The card isn’t always authorised to request offline acceptance of the transaction if the terminal proposed on-line authorization). The terminal should perform the motion that the card requested in the course of card motion evaluation.

Online Processing:

On-line processing allows the card provider to research the transaction info and determine whether or not it desires to authorize or reject the transaction. This lets in the company to check the account fame and follow standards based upon proper limits of threat defined by the card company, the charge scheme and the acquirer. If no valid response is acquired from the host (e.G. Because of communications failure) then the terminal is needed to perform extra Terminal action analysis to manipulate the increased stage of danger, and this could result in the terminal informing the cardboard that it proposes to both accept or decline the transaction regionally.

After on line processing has been finished, the cardboard will examine the end result of the net processing and will authenticate records received from the cardboard issuer. This could bring about the card asking for the terminal to finish the transaction through both accepting or declining the transaction. This request can also fluctuate from the result of on-line processing, however is situation to sure common sense regulations (e.G. The card isn’t always accredited to request recognition of the transaction if the host declined the charge).

Transaction Completed:

While the card processing has been finished, the card may be eliminated. If the transaction has been authorized then charge may be submitted for agreement and any goods or services may be furnished.

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