Hello,
Thank you for contacting us. We do not disclose or keep unnecessary copies of submitted data and generated files. They are kept only for the time necessary to efficiently process API requests and then permanently deleted. A description of the request life cycle can be found here:
http://pdfcrowd.com/api/html-to-pdf-api/#api-ref-securityAlso, API clients can optionally communicate with the API over a secured connection (https).