> For the complete documentation index, see [llms.txt](https://docs.2checkout.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.2checkout.com/json-rpc-api-reference/json-rpc-api-6.0/authentication.md).

# Authentication

Use the **login** method for the authentication process in the 2Checkout system.

## Request parameters

| Parameters     | Type / Description                                                                                                                                 |
| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
| `merchantCode` | <p><strong>Required (String)</strong><br>Your merchant identification code.</p>                                                                    |
| `date`         | <p><strong>Required (String)</strong><br>GMT ISO Date format (e.g. 2010-01-01 12:13:14)</p>                                                        |
| `hash`         | <p><strong>Required (Object)</strong><br>Calculated HMAC\_SHA256 signature based on <code>merchantCode</code> and date, using your secret key.</p> |

### Request sample

```php
<?php

/**
 * @throws JsonException
 */
function callRPC($Request, $host) {
    $curl = curl_init($host);
    curl_setopt($curl, CURLOPT_POST, 1);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, 1);
    curl_setopt($curl, CURLOPT_VERBOSE, true);
    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, 2);
    curl_setopt($curl, CURLOPT_SSLVERSION, 0);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($curl, CURLOPT_HTTPHEADER, array('Content-Type: application/json', 'Accept: application/json'));
    $RequestString = json_encode($Request, JSON_THROW_ON_ERROR);
    curl_setopt($curl, CURLOPT_POSTFIELDS, $RequestString);

    $ResponseString = curl_exec($curl);

    if (!empty($ResponseString)) {
        echo($ResponseString);
        $Response = json_decode($ResponseString, false, 512, JSON_THROW_ON_ERROR);
        if (isset($Response->result)) {
            return $Response->result;
        }
        if (!is_null($Response->error)) {
            echo("Method: {$Request->method}" . PHP_EOL);
            echo("Error: {$Request->error}" . PHP_EOL);
        }
    } else {
        return null;
    }
    return null;
}

$host = 'https://api.2checkout.com/rpc/6.0/';

$merchantCode = "YOUR_MERCHANT_CODE"; // your account's merchant code available in the 'System settings' area of the cPanel: https://secure.2checkout.com/cpanel/account_settings.php
$key = "YOUR_SECRET_KEY"; // your account's secret key available in the 'System settings' area of the cPanel: https://secure.2checkout.com/cpanel/account_settings.php

$string = strlen($merchantCode) . $merchantCode . strlen(gmdate('Y-m-d H:i:s')) . gmdate('Y-m-d H:i:s');
$algo = "sha256";
$hash = hash_hmac($algo, $string, $key);

$i = 1;

$jsonRpcRequest = new stdClass();
$jsonRpcRequest->jsonrpc = '2.0';
$jsonRpcRequest->method = 'login';
$jsonRpcRequest->params = array($merchantCode, gmdate('Y-m-d H:i:s'), $hash, $algo);
$jsonRpcRequest->id = $i++;

try {
    $sessionID = callRPC($jsonRpcRequest, $host);
    echo("Auth token: {$sessionID}" . PHP_EOL);
} catch (JsonException $e) {
    echo("Error: {$e->getMessage()}" . PHP_EOL);
}
```

## Response parameters

| Parameters  | Type / Description                                                                                                                                                                                                                                                             |
| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `sessionID` | <p><strong>String</strong><br>Session identifier, the output of the <strong>Login</strong> method. Include <code>sessionID</code> into all your requests. 2Checkout throws an exception if the values are incorrect. <br>The <code>sessionID</code> expires in 10 minutes.</p> |


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.2checkout.com/json-rpc-api-reference/json-rpc-api-6.0/authentication.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.