# API Reference
source: https://developer.mastercard.com/payment-account-reference-inquiry/documentation/api-reference/index.md

Registered Merchants, Acquirers, or Digital Activity Customers (DACs) can use this service to query the PAR Vault to obtain or generate a Payment Account Reference (PAR), from a Primary Account Number (PAN) or affiliated MDES Token where Mastercard is the Bin Controller. PAR provides an industry-aligned approach designed to help link PAN-based transactions to transactions using associated payment tokens, without using the PAN as the linkage mechanism.
Note: This version is technically identical to v1.3, however, it has been modified for minor cosmetic changes to the structure.
API Specification: `https://static.developer.mastercard.com/content/payment-account-reference-inquiry/swagger/Payment-Account-Inquiry-v1-33.yaml`

You can import this yaml file into Insomnia and use the Mastercard plugin to test this API with the OAuth Authentication [Insomnia Plugin](https://developer.mastercard.com/platform/documentation/using-oauth-1a-to-access-mastercard-apis/#insomnia-plugin).

## Encrypting the Request Payload {#encrypting-the-request-payload}

Refer to [Securing Sensitive Data Using Payload Encryption](https://developer.mastercard.com/platform/documentation/securing-sensitive-data-using-payload-encryption/) for details on how to encrypt the sensitive fields in the POST request payloads.

### Request {#request}

Contents of encryptedData in encryptedPayload prior to encryption:

* *accountNumber* - The Primary Account Number of the account or the affiliated MDES token.

For example:
* JSON

```JSON
{
  "accountNumber": "5412346789012345"
}
```

### Response {#response}

Contents of encryptedData in encryptedPayload after decryption:

* *paymentAccountReference* - The PAR assigned to the PAN.

For example:
* JSON

```JSON
{
  "paymentAccountReference": "512381d9f8e0629211e3949a08002"
}
```