Proprietary firmware is any firmware that has had its use, private modification, copying, or republishing restricted by the producer. Proprietors may enforce restrictions by technical means, such as by restricting source code access, firmware replacement restrictions (by denying complete tooling that may be necessary in order to recompile and replace the firmware), or by legal means, such as through copyright and patents. Alternatives to proprietary firmware may be free (libre) or open-source.