I understand there are laws like the Circumvention of Technological Measure (CTM), Computer Fraud and Abuse Act (CFAA), Digital Millennium Copyright Act (DMCA). According to these laws it's considered 'copyright infringement' to modify software one does not have the copyright to, which basically stops people from 'hacking' any games or software, but nobody is trying to hack the Digital rights management (DRM). That DRM stuff relates to making keygens and cracking software

I have searched Google and not found any cases anywhere regarding someone being sued for 'cheating' in a Singleplayer (offline) game, but due to the way the copyright laws are worded, there seems to be a grey area surrounding this subject.

Here is something I found in my research: Lewis Galoob Toys, Inc. v. Nintendo of America, Inc. - Source: Wikipedia.

In her ruling, Smith compared usage of the Game Genie to "skipping portions of a book" or fast-forwarding through a purchased movie; thus the altered game content did not constitute the creation of a derivative work as Nintendo had argued.

This court case established the legality of using the device "Game Genie" to modify the way a console game is played. But does this legal argument also extend to modifying (or "hacking") the game binary of a single-player game itself?

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    A local modification to your own copy of a game (without distributing the result) might technically be against the terms of usage (e.g. EULA violation) or might be seen as reverse engineering, which is often forbidden in such agreements. But such restrictions are not always enforceable, and breaking a EULA term does not automatically mean you are breaking a law. You will find more about this topic on the site if you search for 'reverse engineering'.
    – Brandin
    Commented Sep 21, 2021 at 12:03
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    Please note that this website is for posting factual questions, not for starting debates. I removed all the ranting, personal opinion and call to activism from this question and condensed it to the actual question being asked. I hope that it can be reopened that way.
    – Philipp
    Commented Sep 21, 2021 at 12:42
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    What is "cheating?" that term is not defined in law. Hacking is defined as unauthorized access. See also: law.stackexchange.com/a/72917/10334
    – Trish
    Commented Sep 22, 2021 at 1:28
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    I like how you say "I have searched Google and not found any cases anywhere regarding someone being sued for 'cheating' in a Singleplayer (offline) game" and then immediately cite a big case about a manufacturer suing over offline single player game cheating...
    – Ron Beyer
    Commented Sep 22, 2021 at 1:56
  • oh sorry @RonBeyer I should've clarified I meant in the nintendo case Galoob was selling the Game Genie 'cheats' not just distributing for free, so they are making money off it as well. But what I should've clarified was I haven't seen anyone who distributed these Singleplayer (offline) 'cheats' for free and got still sued. most of the cases I see they involve money or that they've pissed off the company in some way. For example here: kotaku.com/…. this would just piss off the company
    – Jack
    Commented Sep 22, 2021 at 9:37

2 Answers 2


There is no one-size-fits-all answer to this question. It depends on the game.

The difference between modding and cheating is largely a matter of semantics. In some cases, cheaters can use facilities which are deliberately built into the game, without modifying it (e.g. cheat codes, console commands, etc.). However, it is difficult to see how making use of such facilities could possibly violate any law, regulation, or agreement, and so the rest of this answer will focus on modding.

I think it would help to walk through two specific examples, to illustrate the broad range of possible answers to this question. Here are the examples I chose:

  • The Elder Scrolls V: Skyrim for PC ("Skyrim" for short)
  • Super Mario Odyssey for the Nintendo Switch ("SMO" for short)

Both of these games are single player (although SMO has a minor, optional multiplayer component), and both have been extensively modded by their respective communities.


Skyrim's Creation Kit EULA expressly authorizes modding, and the wording implies that mods are the intellectual property of the modder (because it states that the modder automatically grants a license to Bethesda). Bethesda even permits modders to sell Skyrim mods for real money, which is practically unheard of in the video game industry (even under the very restrictive terms which Bethesda sets for such paid mods). Bethesda's open authorization of and acceptance towards modding, and the fact that they deliberately provide modding tools in the first place, makes it very difficult to characterize Skyrim mods as anything other than legal.

However, if you try to circumvent Steam's DRM, or sell mods for money without going through Bethesda's paid mods program, then you are certainly violating one or both of the EULA linked above and the Steam EULA. Such violation could subject you to civil liability under a variety of legal theories, but in practice, the most likely outcome is that Valve terminates your Steam account (as the Steam Subscriber Agreement says they can) and you lose all the games you previously purchased. But they're not going to waste their time suing you, unless you somehow make a nuisance of yourself.

Paid mods, outside of Bethesda's system, might even be criminal copyright infringement, although I would be rather surprised if it were actually prosecuted as such (the DOJ generally has more important things to worry about, and copyright infringement can't be prosecuted at the state level). If you're willing to call civil liability and unlikely-to-be-prosecuted criminal liability "illegal," then Skyrim modding can be illegal if you violate the terms and conditions.

One other thing: The terms linked above also say that mods ("New Materials") can only be distributed "to other authorized users who have purchased the Product, solely for use with such users’ own authorized copies of such Product and in accordance with and subject to the terms and conditions of this Agreement and all applicable laws." In other words, you are not supposed to distribute mods to users of pirated copies, which is probably impractical to enforce in any meaningful way (modding sites generally make no effort to verify that individual users have actually purchased the game, although in theory it might be technically possible to do so). In my experience, modders are often quite hostile to users of pirated copies of Skyrim, because such copies are nonstandard and more difficult to support. Bethesda evidently views this in-practice hostility as "good enough."


SMO is a completely different ballgame. Nintendo does not provide modding tools for either the game or the console on which it runs. Furthermore, Nintendo has repeatedly updated the console to prevent people from modding it, and to break or render ineffective existing techniques for such modding. Their stated rationale for this activity is to prevent users from running pirated games on their consoles. Therefore, this brings the whole thing into the scope of the DMCA's infamous anti-circumvention provisions. 17 USC 1201 provides that:

(A) No person shall circumvent a technological measure that effectively controls access to a work protected under this title. The prohibition contained in the preceding sentence shall take effect at the end of the 2-year period beginning on the date of the enactment of this chapter.


(3) As used in this subsection—
(A) to “circumvent a technological measure” means to descramble a scrambled work, to decrypt an encrypted work, or otherwise to avoid, bypass, remove, deactivate, or impair a technological measure, without the authority of the copyright owner; and
(B) a technological measure “effectively controls access to a work” if the measure, in the ordinary course of its operation, requires the application of information, or a process or a treatment, with the authority of the copyright owner, to gain access to the work.

It doesn't matter whether you are trying to commit piracy or not. It only matters that:

  1. You "avoid, bypass, remove, deactivate, or impair a technological measure," and
  2. The technological measure "effectively controls access to a work" as defined above, and
  3. You did it without Nintendo's permission, and
  4. Your action doesn't fall under one of the permanent exceptions listed in 17 USC 1201, nor under any of the 3-year exceptions which the Librarian of Congress is authorized to temporarily grant.

So by breaking the DRM on the Nintendo Switch, which is a prerequisite for modifying SMO, you necessarily violate 17 USC 1201, unless you fall into one of the exceptions. Of those, the only one which is even colorably relevant is subsection (f):

(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.

("This title" means Title 17, which is the entire copyright law of the United States.)

This is basically saying that you can bypass DRM for the limited purpose of making "an independently created computer program" interoperate with "other programs." The problem here is that most mods are going to be derivative works of some kind, and just creating a derivative work, even if you never distribute it, is generally copyright infringement under 17 USC 106. And the exception-to-the-exception is that it doesn't apply whenever you infringe any copyright, regardless of whether the DRM was intended to prevent you from committing that specific act of infringement or not.

There is some room for debate over whether mods can or should be considered fair use, which is beyond the scope of this discussion. Suffice it to say, it's a complicated, fact-specific inquiry, which is not compatible with sweeping "modding is legal/illegal" statements. We also don't have much good case law for it. Regardless, the Switch's EULA expressly prohibits modding, and so you would still be liable for a contractual violation anyway.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – Dale M
    Commented Sep 23, 2021 at 21:16

The answer, of course, is "it depends." I can see at least 3 main issues here. They are as following:

  1. Is there any type on encryption that is used to protect the information the user would need to access in order to cheat? If there is, then they can (in theory) be sued for violating DMCA. Any claims about the strength of the encryption (or lack of it) would be claims about facts of the case (and not about the law). So they would have to be resolved by the finder of fact (e.g. a jury at a trial).

  2. Was there a contract which stipulated that using a licensed copy of the game implies a promise not to reverse-engineer the game? If there was such a clause in the license agreement, then distributing a cheat device (whether software or hardware) would be a form of tortious interference.

  3. Do you plan to purchase (or download for free) the device that does this or do you plan to distribute it?
    (a). The modified version of the game would be derivative work under the copyright law. To extend the book analogy from the quote you found, it would be akin to reading a book with the pages of the book removed (rather than skipping the pages in a book which still contains the pages). However, copyright law only deals with distribution of copied or derivative works -- not with consumption of such works.
    (b). A different user, in a response to a different question had made the claim that a simple modification of RAM would likely not be considered a derivative work because such prohibition (in a contract) would be considered "an unconscionable clause and void."
    (c). Does distributing a device which automatically creates a derivative work, out of the original, amount to distributing a derivative work? Unless there is a clear litmus test for it, it would be a decision on the facts of the case (and would be decided at trial if it gets that far).

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    "copyright law only deals with distribution of copied or derivative works -- not with consumption of such works." This is incorrect in the US. US law makes merely creating a derivative work, or making a copy constitute infringement if done without authorization. Suits usually follow distribution, because that is how owners learn of the infringement. But 17 USC 106 is clear that the owner has the exclusive righjt to prepare a derivative work (or authorize it), and to make a copy (or authorize it). Commented Sep 21, 2021 at 15:01
  • @DavidSiegel it maybe a distinction without a difference for the purposes of this question. I am going to have to read it again, but if I remember correctly If entity B creates a work which is derivative of the one copyrighted by entity A, the use of the derivative work by entity C is not a violation of A's copyright. The creation of the derivative work by B was the violation (because it was done in order to distribute it to C). Writing a script which is based on characters of a popular novel is creation of derivative work, but I am not sure that the act of writing is a violation.
    – grovkin
    Commented Sep 21, 2021 at 15:14
  • Showing it to someone would be though. I admit I am forgetting the details right now though. I'll read it and get back to you.
    – grovkin
    Commented Sep 21, 2021 at 15:14
  • In US law, the mere act of writing such a derivative work by B is an infringement, even if B had no intent to show it to anyone, and never does so. In practice, of course, suit is unlikely unless the work is somehow distributed. But if D discovers the work and reports it to A, A could sue. Or if D discovers the work and publishes it. 17 USC 106 (2) is clear on this. See copyright.gov/title17/92chap1.html#106 for the law. Commented Sep 21, 2021 at 15:21
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    Re (2): If you breach the license agreement, but the plaintiff has suffered no actual monetary damages arising from your breach, I think the average court is going to look askance at a tortious interference lawsuit. There would probably need to be some theory by which the plaintiff is actually injured by such a breach.
    – Kevin
    Commented Sep 21, 2021 at 21:56

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