A free standard or libre standard is a standard whose specification is publicly available. The concept of Free/Libre standards emerged in the software industry as a reaction against closed de facto "standards" which served to reinforce monopolies. Users of a free standard have the same four freedoms associated with free software, and the freedom to participate in its development process. The standardisation process typically requires a complete free software reference implementation, which demonstrates that it is implementable and renders it usable. A libre standard is not patent-encumbered.