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"issuer scripts"

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Issuer Script Results field values shown on a POS terminal screen

Credit Card

Issuer Script Results

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.

Diagram explaining what an EMV Issuer Script is and how it updates card chip parameters

EMV

What Is an EMV Issuer Script?

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.

Diagram illustrating the EMV Tag-Length-Value (TLV) data structure used in card transactions

Online & Authorization

What are EMV Tags?

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.

Diagram illustrating the ISO 8583 F55 field structure for ICC system related data

ISO 8583

ISO 8583 Field Descriptions (F55)

F55 - INTEGRATED CIRCUIT CARD (ICC) SYSTEM RELATED DATA: the field where EMV data is written on chip cards. It consists of components such as Position, Private Data Subelements, PDS Tag, PDS Length, and PDS Value...

Diagram showing the structure of the Card Verification Results (CVR) data element

Credit Card

CVR (Card Verification Results)

CVR (Card Verification Results) refers to the results of checks performed on the card. In short, it can be described as keeping the card's transaction log. BYTE 1 Bit 8-7: 00 = The second GENERATE AC command returned an AAC cryptogram (decline)...

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.

EMV application block command

EMV

What Is the Application Block Command?

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.

Table of EMV Transaction Status Information (TSI) bit definitions

Merchant & POS

Transaction Status Information (TSI)

Contains the EMV steps performed by the Terminal in a transaction. The TSI fields, their possible values, and descriptions of the values are shown below.

Diagram of the EMV Card Block command process

EMV

What is the Card Block command?

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.