public function rebindContentKey($contentKey, $x509Certificate)
    {
        $contentKeyId = Utilities::getEntityId(
            $contentKey,
            'WindowsAzure\MediaServices\Models\ContentKey'
        );
        $contentKeyId = urlencode($contentKeyId);

        $x509Certificate = urlencode($x509Certificate);

        $method = Resources::HTTP_GET;
        $headers = [];
        $postParams = [];
        $queryParams = [];
        $statusCode = Resources::STATUS_OK;
        $path = "RebindContentKey?id='{$contentKeyId}'".
            "&x509Certificate='{$x509Certificate}'";

        $response = $this->sendHttp(
            $method,
            $headers,
            $queryParams,
            $postParams,
            $path,
            $statusCode
        );

        $key = (string) simplexml_load_string($response->getBody());

        return base64_decode($key);
    }