A software license is a legal instrument (usually by way of contract law, with or without printed material) governing the use or redistribution of software. Under United States copyright law, all

software Software is a set of computer programs and associated software documentation, documentation and data (computing), data. This is in contrast to Computer hardware, hardware, from which the system is built and which actually performs the work. ...

is copyright protected, in both

source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the w ...

and

object code In computing, object code or object module is the product of a compiler In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ...

forms, unless that software was developed by the United States Government, in which case it cannot be copyrighted. Authors of copyrighted software can donate their software to the

public domain The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because those rights have expired, ...

, in which case it is also not covered by copyright and, as a result, cannot be licensed. A typical software license grants the

licensee A licensee can mean the holder of a license or, in U.S. tort law, a licensee is a person who is on the property of another, despite the fact that the property is not open to the general public, because the owner of the property has allowed the li ...

, typically an

end-user In product development, an end user (sometimes end-user) is a person who ultimately uses or is intended to ultimately use a product. The end user stands in contrast to users who support or maintain the product, such as sysops, system administrato ...

, permission to use one or more copies of software in ways where such a use would otherwise potentially constitute copyright infringement of the software owner's exclusive rights under copyright.

Software licenses and copyright law

Most distributed software can be categorized according to its license type (see table). Two common categories for software under copyright law, and therefore with licenses which grant the

specific rights, are

proprietary software Proprietary software is software that is deemed within the free and open-source software to be non-free because its creator, publisher, or other rightsholder or rightsholder partner exercises a legal monopoly afforded by modern copyright and i ...

and free and open-source software (FOSS). The distinct conceptual difference between the two is the granting of rights to modify and re-use a software product obtained by a customer: FOSS software licenses both rights to the customer and therefore bundles the modifiable

with the software (" open-source"), while proprietary software typically does not license these rights and therefore keeps the source code hidden ("

closed source Proprietary software is software that is deemed within the free and open-source software to be non-free because its creator, publisher, or other rightsholder or rightsholder partner exercises a legal monopoly afforded by modern copyright and inte ...

"). In addition to granting rights and imposing restrictions on the use of copyrighted software, software licenses typically contain provisions which allocate liability and responsibility between the parties entering into the license agreement. In enterprise and commercial software transactions, these terms often include limitations of liability, warranties and warranty disclaimers, and indemnity if the software infringes intellectual property rights of anyone. Unlicensed software outside the scope of copyright protection is either

public domain software Public-domain software is software that has been placed in the public domain, in other words, software for which there is absolutely no ownership such as copyright, trademark, or patent. Software in the public domain can be modified, distributed, ...

(PD) or software which is non-distributed, non-licensed and handled as internal business

trade secret Trade secrets are a type of intellectual property that includes formulas, practices, processes, designs, instruments, patterns, or compilations of information that have inherent economic value because they are not generally known or readily ...

. Contrary to popular belief, distributed unlicensed software (not in the public domain) is fully copyright protected, and therefore legally unusable (as no usage rights at all are granted by a license) until it passes into public domain after the

copyright term The copyright term is the length of time copyright subsists in a work before it passes into the public domain. In most of the world, this length of time is the life of the author plus either 50 or 70 years. Length of copyright Copyright subsists f ...

has expired. Examples of this are unauthorized

software leak An internet leak is the unauthorized release of information over the internet. Various types of information and data can be, and have been, "leaked" to the Internet, the most common being personal information, computer software and source code, a ...

s or software projects which are placed on public software repositories like

GitHub GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking, software feature requests, task management, continu ...

without a specified license. As voluntarily handing software into the public domain (before reaching the copyright term) is problematic in some jurisdictions (for instance the

law of Germany The law of Germany (german: das Recht Deutschlands), that being the modern German legal system (german: Deutsches Rechtssystem), is a system of civil law which is founded on the principles laid out by the Basic Law for the Federal Republic of G ...

), there are also licenses granting PD-like rights, for instance the

CC0 A Creative Commons (CC) license is one of several public copyright licenses that enable the free distribution of an otherwise copyrighted "work".A "work" is any creative material made by a person. A painting, a graphic, a book, a song/lyric ...

WTFPL WTFPL is a permissive free software license. As a public domain like license, the WTFPL is essentially the same as dedication to the public domain. It allows redistribution and modification of the work under any terms. The title is an abbreviat ...

Ownership vs. licensing

Many

proprietary {{Short pages monitor