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Merchant & POS
In EMV transactions, Application Selection is the process of choosing among the applications supported by both the card and the terminal. It is the first stage of authorization, so it is very important. This post covers the PSE and List of AIDs methods.
EMV
DFN is the abbreviation for Dedicated File Name. It defines the name of the DF (Dedicated File) as described in ISO/IEC 7816-4. It is the data found in Tag 84, 5 to 16 characters in length.
Credit Card
PSE (Payment System Environment) is a directory on the card named 1PAY.SYS.DDF01 for a contact chip and 2PAY.SYS.DDF01 for a contactless chip. The Candidate List built via PSE is called indirect or implicit Application Selection.
EMV
The Card Block command is used after card issuance to deactivate all applications within the ICC, including applications that could be selected indirectly. The components of the command are explained below.
Credit Card
While it is true that, with technological advancement, the trend of using payment transactions without a physical card via mobile phones has increased, there are many reasons why cards are still physically printed and delivered to customers.
EMV
AID tells the terminal which applications are present on a chip when a transaction is performed via POS/ATM. It is a 5-16 digit value in Tag 9F06, used to identify chip applications by card scheme.
EMV
The Application Block command is sent to invalidate the selected application on a card after the card has been issued. Unlike Card Block, it can be reversed.
Payment Systems
In payment or cash withdrawal transactions, the TR QR Code is generated by the POS or ATM. The card issuing bank must build its systems to read and act on this code. Errors usually stem from mishandling the long and short QR code flows, which are explained here.
Credit Card
A combo card is a next-generation card that combines both a credit card and a debit card on a single card. Although designs vary visually, the front typically carries the credit card information and the back the debit card information.
Merchant & POS
Contains the terminal-resident data objects (tags and lengths) that the ICC needs when processing the GET PROCESSING OPTIONS command. In short, it is the list of information the card requests from the terminal before starting the transaction.
Online & Authorization
In EMV, data is stored in Tag-Length-Value (TLV) format, and it is carried between the card, the POS terminal, and the authorization system in this same format. This post lists every EMV Tag, its type, and its description.
Online & Authorization
ISO/IEC 7816-5 defines how to use an application identifier to determine whether an application is present on a card and/or to retrieve the application on the card.