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Credit Card
Issuer Script Results is the field that shows the results of the Issuer Script commands sent to the card. This post explains its byte and bit values, what an issuer script is, why the results matter, and what happens when a command fails.
Online & Authorization
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).
HSM & Security
Secure Element Issuer is the stakeholder that provides, maintains, and updates the secure element in cases where mobile payment application and card data are stored in the secure element inside a mobile phone.
Credit Card
Issuer Identification Number (IIN) is the first 6 digits of 16-digit cards and the first 8 digits of 19-digit cards. It is more commonly known as BIN (Bank Identification Number). Learn what the IIN table holds and how to look one up.
Merchant & POS
The most important part of issuer data definitions is that they are built around your own bank's or institution's developments and application flows. Missing BINs can break installments, rewards and routing on POS devices.
EMV
An EMV Issuer Script is a system that lets the issuer (the institution that issues the card) update and change the parameters and values on the card chip while it remains in use, reducing fraud over the card's lifetime.
Merchant & POS
In EMV-based debit card transactions, PIN verification is decisive for both security and liability. What happens when a card that only supports online PIN is sent to the issuer without a PIN, and the issuer approves it? Who owns the risk?
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.
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.
Online & Authorization
A reference guide to authorization response codes seen on POS and ATM transactions, with plain-language explanations of what each code means and what to do about it.
Payment Systems
The domestic authorization flow for below-CVM-limit online contactless transactions has changed. Issuers can now ask the cardholder for a PIN or request card insertion instead of simply approving or declining. This post explains the CVM list and the new DE48 PDS22 and DE39 = 65 message flows.
Credit Card
In the standard authorization flow, the transaction is initiated by the acquirer (POS bank) and forwarded to the issuer (card-issuing institution). The process is completed once the issuer responds. However, this isn't always possible; when the issuer fails to respond, BKM steps in...