Writing open-source software to read proprietary binary files

Question

Consider a proprietary program that produces binary files for storage (e.g. .doc). Let's say a developer wants to write an open source program that reads those binary files. Is there anything to legally forbid him to do so and to distribute that code? My initial guess is:

• If the user of the open source code also uses the proprietary software and agreed to the proprietary software EULA, and the EULA forbids reading the files with any other software, then the use of the open source software consists a breach of the EULA for that user.

• If the user of the open source code also uses the proprietary software and agreed to the proprietary software EULA, but the EULA has no provision for forbidding the use of other software to read the binary output, then the user can use the open source software.

• If the user of the open source code does not use the proprietary software, he/she is not bound by the EULA, and therefore he can legally use any kind of software, including open source, to read such a binary file created and sent to him by someone else.

These are just guesses though. Does anyone know what the answer to this question is? Can a company take a developer to court because he/she wrote and distributed open source software to read its output files?

Answer 1

Can a company take a developer to court

Yes, for anything. And they do. The bigger the company, the more likely, even if they don't have a legally defensible position. Often, they have deep pockets, and are just looking to bankrupt the developer.

Go speak with lawyer on this. Do not rely on the wisdom of internet forums.

Answer 2

The lawyer answer to this is "it depends". And that is most likely the right answer. You can't make any blanket statements on any binary file format. You'd need to research if the file format is patented, what the EULA of the program that generates the format says, etc.

Disclaimer: I'm no lawyer.