> ## Documentation Index
> Fetch the complete documentation index at: https://devzone.nayax.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Dynamic Key Exchange

Once a key needs to be renewed (the renewal interval will be discussed during project setup), a Cortina RenewKey request will be sent. The request will include all the details of the current key in the `CurrentKeyData` object. The Payment Gateway should send the new key data in the `NewKeyData` object of the response, as in the example below:

```json theme={null}
"NewKeyData": {
    "EncryptedKeyValue": "D0112P0AB01N00008C27C2DD44ACF35513DCA16B10B7FB9AD47550091AF4FF37C01002E5BA04A1D05057291A4B0EBCA6EE46940224BCE55F",
    "Kcv": "BC4012",
    "ExternalKeyId": "376",
    "additionalProperties": {}
  }
```

Where:

* **EncryptedKeyValue**	= the encrypted Key Value, encrypted with the ZMK shared.
* **Kcv** = the new Key Check value (content is bytes)
* **ExternalKeyId** = The new External Key ID in the payment gateway system.