This depends on Bug 423894. ZIP files created on Windows may have encoding problems. As a solution, we can use unar's -e and -E parameters to specify the correct encodings. It would be nice if we can choose the encoding via Ark's GUI, just like you can choose the text encoding in Firefox. Bug 393901, Bug 324978 and Bug 378904 will be benefited by this feature.
Are there any particular programs on Windows that create known issues with extracting using Ark? This way we can test them.
Windows' built-in "compress to ZIP" feature in File Explorer has this issue, and can be reproduced with a non-English Windows installation and files with non-English names. For example, in Windows XP (Japanese): 1. Create a file with Japanese characters, e.g. "あいうえお.txt" 2. Right click the file / folder and "Send to" > "Compressed (zipped) folder" (Japanese: "送る" > "圧縮（zip 形式）フォルダー") 3. The ZIP file created will use the Shift_JIS encoding. 4. Thus, when opening the created file with 7z or unzip, the filename cannot be properly interpreted.
See https://bugs.kde.org/show_bug.cgi?id=393901#c12 With that solution we would be able to handle non-unicode password with the libzip plugin itself.