> There is an unofficial unrar that is free and open-source software, but there is no free and open-source rar as creating one is prohibited by the RAR license.<p>From the license (EULA), I assume this is the relevant part:<p>> You may not use, copy, emulate, clone, rent, lease, sell, modify, decompile, disassemble, otherwise reverse engineer, or transfer the licensed software, or any subset of the licensed software, except as provided for in this agreement. Any such unauthorized use shall result in immediate and automatic termination of this license and may result in criminal and/or civil prosecution.<p>> Neither RAR binary code, WinRAR binary code, UnRAR source or UnRAR binary code may be used or reverse engineered to re-create the RAR compression algorithm, which is proprietary, without written permission.<p>> The software may be using components developed and/or copyrighted by third parties. Please read "Acknowledgments" help file topic for WinRAR or acknow.txt text file for other RAR versions for details.<p>Is this actually enforceable? If yes, are there worse outcomes apart from revoking the license? And I mean, the open source unrar, which is supposedly fine, doesn't come with an EULA like this. So it's probably not binding for reverse engineering based on the open source unrar.<p>edit: I mean if there is a separate patent, then it's a different issue.