Last modified on 18 March 2015, at 05:15

Reverse Engineering/Legal Aspects

It is quite often the case that reverse code engineering a software product is teetering on the border of legal and illegal. Note that reverse engineering a competing car or a weapon is never legally challenged, nor was reverse engineering software a few decades ago. So as a reverse engineer, you should know your rights and the rights of the software owner. This chapter will focus on just that, exploring issues surrounding patents, copyrights, and licensed software. Even if you play by the rules, you are not immune to harassment lawsuits. (NB: The material here reflects the legal position in the USA. Other juridictions may have different laws.)

Patented SoftwareEdit

Explain the rights of the software owner under the patent law

Copyrighted SoftwareEdit

There are laws about the copyright that someone who reverse-engineers must take care of in open source projects, and the common approach to this problem is to divide the programmers into 2 groups:

  1. The one who disassembles the code of the program/firmware and writes the specifications.
  2. The second group that makes a program using these specifications.

Fair UseEdit

Under a few circumstances, fair use allows the reproduction of copyrighted material without the owner's permission. The Copyright Act of 1976, 17 U.S.C. § 107 states specifically:

Notwithstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work, including such use by reproduction in copies or phonorecords or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include—

  1. the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
  2. the nature of the copyrighted work;
  3. the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
  4. the effect of the use upon the potential market for or value of the copyrighted work.

The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors.

In terms of reverse engineering and fair use, the law tends to favor the reverser. However, negatively effecting the value of the original product will almost never result in it being categorized as "fair use." Also keep in mind that fair use does not permit breaking the user license terms.

It needs to be noted that fair use is not black and white. The line between fair use and copyright infringement is very gray. Unless you are very confident about what you are doing, you shouldn't do it.

Digital Millennium Copyright ActEdit

The Digital Millennium Copyright Act was put into place in 1998 in order to make any service or device with purpose of undermining or removing DRM (Digital Rights Management) copyright infringement. The act forbids any service or device from being designed to circumvent, or even being marketed to circumvent any DRM.

There is, however, an exception in the DMCA stating that reverse engineering can be done under the purposes of inter-operability between software components.[1] It states the following:


  1. Notwithstanding the provisions of subsection (a)(1)(A), a person who has lawfully obtained the right to use a copy of a computer program may circumvent a technological measure that effectively controls access to a particular portion of that program for the sole purpose of identifying and analyzing those elements of the program that are necessary to achieve interoperability of an independently created computer program with other programs, and that have not previously been readily available to the person engaging in the circumvention, to the extent any such acts of identification and analysis do not constitute infringement under this title.
  2. Notwithstanding the provisions of subsections (a)(2) and (b), a person may develop and employ technological means to circumvent a technological measure, or to circumvent protection afforded by a technological measure, in order to enable the identification and analysis under paragraph (1), or for the purpose of enabling interoperability of an independently created computer program with other programs, if such means are necessary to achieve such interoperability, to the extent that doing so does not constitute infringement under this title.
  3. The information acquired through the acts permitted under paragraph (1), and the means permitted under paragraph (2), may be made available to others if the person referred to in paragraph (1) or (2), as the case may be, provides such information or means solely for the purpose of enabling interoperability of an independently created computer program with other programs, and to the extent that doing so does not constitute infringement under this title or violate applicable law other than this section.
  4. For purposes of this subsection, the term ‘interoperability’ means the ability of computer programs to exchange information, and of such programs mutually to use the information which has been exchanged.

Fair use does still apply. However, it is not fair use to gain unauthorized access to copyrighted work.[2]

End User License AgreementEdit

An end user license agreement (or EULA) is a legal contract between the software manufacturer and the user. It explains the terms under which the user may use the software, giving a list of conditions of what the user may and may not do. This contract can states anything from the number of copies that can be made to conditions under which it can be reverse engineered.

EULA and Fair UseEdit

Fair use seems to be safe ground for reverse engineers, almost always using it as a defense. However, an EULA is a legally binding contract. If a user agrees to terms which are in conflict with fair use, the user has effectively waved their rights to fair use.

In the case of Davidson & Associates v. Jung [3], Ross Combs, Rob Crittenden, and Jim Jung reverse engineered Blizzard's protocol language to allow gamers to play pirated video games online. In this case, the reverses agreed to an EULA and TOU (Terms of Use) prohibiting reverse engineering. The judge found the EULA and TOU to be enforceable by law and that a user's right to reverse engineer a product can be contractually waved.

Famous CasesEdit

Atari Games Corp. v. Nintendo of America Inc. [4]Edit

When Nintendo came out with the Nintendo Entertainment System, they designed a program, the 10NES, to prevent unauthorized video games from working on the NES. In order to make an authorized game, you had to become licensed with Nintendo. And the license agreement basically stated that a company could only make five games per year and prevented them from selling the same games to other home entertainment systems.

Atari attempted to crack the 10NES in order to bypass any need for a restrictive licensee agreement. In 1986 they purchased some Nintendos and started reverse engineering. By chemically dissolving top layers of the chip containing the 10NES, they were able to use a microscope to physically look the bits and accrue some of the object code. The object code was then decompiled to source. However, Atari was unable to completely reverse the 10NES using this method.

In 1988, Atari requested a copy of the 10NES source code from the Copyright Office. To get the Copyright Office to comply, they lied and said they were involved in an infringement lawsuit with Nintendo.

Once Atari completely understood the 10NES program, they built a program that defeated it. In 1989, Nintendo filed charges against them for unfair competition, patent infringement, copyright infringement, and trade secret violations.

One of Atari's defenses was that reverse engineering was fair use under the copyright law. In the end, the courts decided the act of chemically peeling back the chip and looking at the bits to get the object code on systems they purchased was fair use. It was expected that the courts would find Atari at fault for copyright infringement for stealing the source from the Copyright Office. However, in 1994 Atari and Nintendo settled out of court.

Sega Enterprises Ltd. v. Accolade Inc. [5]Edit

This case concerned Sega's video game console and cartridges. The cartridges had a 20-25 byte code segment which was interrogated by the console, as a security measure.

Accolade disassembled the code which was common to three different Sega games cartridges, to find the security segment, and included it in competing games cartridges.

The Ninth Circuit held this disassembly to be a permitted "fair use" of the copyright in the games programs that the disassembly of copyrighted object code as a necessary step in its examination of the unprotected ideas and functional concepts embodied in the code is a fair use that is privileged by section 107 of the Copyright Act. Because disassembly was the only means of gaining access to those unprotected aspects of the program, and because Accolade has a legitimate interest in gaining such access (in order to determine how to make its cartridges compatible with the Genesis console).

Jon Johansen CaseEdit

Give a description of this case

Further ReadingEdit