A software vendor delineates the specific terms of use in an end - user license agreement (EULA). The user may agree to this contract in writing, interactively on screen (clickwrap), or by opening the box containing the software (shrink wrap licensing). License agreements are usually not negotiable. Software patents grant exclusive rights to algorithms, software features, or other patentable subject matter, with coverage varying by jurisdiction. Vendors sometimes grant patent rights to the user in the license agreement. The source code for a piece of software is routinely handled as a trade secret. Occasionally, software is made available with fewer restrictions on licensing or source - code access; such software is known as "free '' or "open - source. ''
which type of software has no restrictions from the copyright holder and can be modified
"free '' or "open - source. ''