Create signed cookies using PHP

The following code example is similar to the example in the Create a URL signature using PHP in that it creates a link to a video. However, instead of signing the URL in the code, this example signs the cookies with the create_signed_cookies() function. The client-side player uses the cookies to authenticate each request to the CloudFront distribution.

This approach is useful to stream content, such as HTTP Live Streaming (HLS) or Dynamic Adaptive Streaming over HTTP (DASH), where the client needs to make multiple requests to retrieve the manifest, segments, and related playback assets. By using signed cookies, the client can authenticate each request without needing to generate a new signed URL for each segment.

The following sections breaks down the code example into individual parts. You can find the complete code sample below.

Create the RSA SHA-1 signature

This code example does the following:

Create the signed cookies

The following code constructs a creates the signed cookies, using the following cookie attributes: CloudFront-Expires, CloudFront-Signature, and CloudFront-Key-Pair-Id. The code uses a custom policy.

function create_signed_cookies($resource, $private_key_filename, $key_pair_id, $expires, $client_ip = null) {
    $policy = array(
        'Statement' => array(
            array(
                'Resource' => $resource,
                'Condition' => array(
                    'DateLessThan' => array('AWS:EpochTime' => $expires)
                )
            )
        )
    );

    if ($client_ip) {
        $policy['Statement'][0]['Condition']['IpAddress'] = array('AWS:SourceIp' => $client_ip . '/32');
    }

    $policy = json_encode($policy);
    $encoded_policy = url_safe_base64_encode($policy);
    $signature = rsa_sha1_sign($policy, $private_key_filename);
    $encoded_signature = url_safe_base64_encode($signature);

    return array(
        'CloudFront-Policy' => $encoded_policy,
        'CloudFront-Signature' => $encoded_signature,
        'CloudFront-Key-Pair-Id' => $key_pair_id
    );
}

For more information, see Set signed cookies using a custom policy.

Full code

The following example code provides a complete demonstration of creating CloudFront signed cookies with PHP. You can download the full example from the demo-php.zip file.

In the following example, you can modify the $policy Condition element to allow both IPv4 and IPv6 address ranges. For an example, see Using IPv6 addresses in IAM policies in the Amazon Simple Storage Service User Guide.

<?php

function rsa_sha1_sign($policy, $private_key_filename) {
    $signature = "";
    $fp = fopen($private_key_filename, "r");
    $priv_key = fread($fp, 8192);
    fclose($fp);
    $pkeyid = openssl_get_privatekey($priv_key);
    openssl_sign($policy, $signature, $pkeyid);
    openssl_free_key($pkeyid);
    return $signature;
}

function url_safe_base64_encode($value) {
    $encoded = base64_encode($value);
    return str_replace(
        array('+', '=', '/'),
        array('-', '_', '~'),
        $encoded);
}

function create_signed_cookies($resource, $private_key_filename, $key_pair_id, $expires, $client_ip = null) {
    $policy = array(
        'Statement' => array(
            array(
                'Resource' => $resource,
                'Condition' => array(
                    'DateLessThan' => array('AWS:EpochTime' => $expires)
                )
            )
        )
    );

    if ($client_ip) {
        $policy['Statement'][0]['Condition']['IpAddress'] = array('AWS:SourceIp' => $client_ip . '/32');
    }

    $policy = json_encode($policy);
    $encoded_policy = url_safe_base64_encode($policy);
    $signature = rsa_sha1_sign($policy, $private_key_filename);
    $encoded_signature = url_safe_base64_encode($signature);

    return array(
        'CloudFront-Policy' => $encoded_policy,
        'CloudFront-Signature' => $encoded_signature,
        'CloudFront-Key-Pair-Id' => $key_pair_id
    );
}



$private_key_filename = '/home/test/secure/example-priv-key.pem';
$key_pair_id = 'K2JCJMDEHXQW5F';
$base_url = 'https://d1234.cloudfront.net';

$expires = time() + 3600; // 1 hour from now

// Get the viewer real IP from the x-forward-for header as $_SERVER['REMOTE_ADDR'] will return viewer facing IP. An alternative option is to use CloudFront-Viewer-Address header. Note that this header is a trusted CloudFront immutable header. Example format: IP:PORT ("CloudFront-Viewer-Address": "1.2.3.4:12345")
$client_ip = $_SERVER['HTTP_X_FORWARDED_FOR'];


// For HLS manifest and segments (using wildcard)
$hls_resource = $base_url . '/sign/*';
$signed_cookies = create_signed_cookies($hls_resource, $private_key_filename, $key_pair_id, $expires, $client_ip);

// Set the cookies
$cookie_domain = parse_url($base_url, PHP_URL_HOST);
foreach ($signed_cookies as $name => $value) {
    setcookie($name, $value, $expires, '/', $cookie_domain, true, true);
}

?>

<!DOCTYPE html>
<html>
<head>
    <title>CloudFront Signed HLS Stream with Cookies</title>
</head>
<body>
    <h1>Amazon CloudFront Signed HLS Stream with Cookies</h1>
    <h2>Expires at <?php echo gmdate('Y-m-d H:i:s T', $expires); ?> only viewable by IP <?php echo $client_ip; ?></h2>
    
    <div id='hls-video'>
        <video id="video" width="640" height="360" controls></video>
    </div>

    <script src="https://cdn.jsdelivr.net/npm/hls.js@latest"></script>
    <script>
        var video = document.getElementById('video');
        var manifestUrl = '<?php echo $base_url; ?>/sign/manifest.m3u8';
        
        if (Hls.isSupported()) {
            var hls = new Hls();
            hls.loadSource(manifestUrl);
            hls.attachMedia(video);
        }
        else if (video.canPlayType('application/vnd.apple.mpegurl')) {
            video.src = manifestUrl;
        }
    </script>
</body>
</html>

Instead of using signed cookies, you can use signed URLs. For more information, see Create a URL signature using PHP.