What happens when I include parts of code(maybe logic/algo, design approach and change its implementation or implement it in a different programming language) of an open-source copy left software in my software and try to make it proprietary? So how will proprietary license issuing authorities verify authenticity of my software(code)? I will claim it as my original work and will never acknowledge that I built it by referencing an open-source work.

1 Answer 1


What “proprietary license issuing authorities”? There is no such thing.

You sell your software for money with a proprietary license. Someone suspects you copied someone else’s code and tells the copyright holder. The copyright holder can be nice and ask you to stop selling under a proprietary license, tell all your customers that your software is under an open source license, and/or pay them money.

Or they take you straight to court. You will be forced to show the evidence (your source code) to their lawyers, they will find the evidence, and sue you for the maximum damages.

BTW Making false claims in court is a serious crime, like lying that you never copied any one’s code.

  • 1
    This answer misses the key part of the question: how will people know (or even suspect) that the “proprietary” software includes copylefted software to begin with? And this answer has too much focus on money: a lot of proprietary software is not libre (free as in freedom), but it is gratis (free as in beer) (that basically means you get to use it without paying money, but you don’t get the rights to change it etc). Mar 27, 2022 at 14:02
  • I would suggest that the "how will people know" part is off topic on law. This has happened.
    – User65535
    Mar 28, 2022 at 11:38

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