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# EMV Response Tags

When processing EMV contact credit card transactions, including the EMV response tags in your authorization/sale response is critical to ensure seamless communication between the issuer, terminal, and chip card.

* **Mandatory** EMV Response tags:
  * Tag 8A:  Authorization Response Code
  * Tag 91:  Issuer Authentication Data
* **Optional** EMV response tags:
  * Tag 71 & Tag 72: Issuer Scripts

These tags carry issuer-provided instructions (scripts) that the terminal sends back to the card. They update card parameters or manage lifecycle events (e.g., block cards and update limits).

Failing to return the mandatory EMV response tags in a contact transaction (8A and 91), or returning them incorrectly, may cause the transaction to fail during the second Generate AC step (Second GenAC) and be declined.\
In case the transaction is declined due to incorrect response tags, a Cortina Cancel/Void will be sent with `ReasonCode` as 17 or 18.

## How to implement

Return the tag value to the relevant field in the "EMVTags" object for each contact transaction response.

```json theme={null}
"EMVTags": {
"Tag91": "A93381BFF8C5E9EC0012",
"Tag8A": "3030",
"Tag71": "860D8424000008D466284E10D1FF7C",
"Tag72": "860D8424000008D466284E10D1FF7C"}
```