Point of the situation with the development of zip extension version 1.14.0 which implements support of encrypted archives.
This new feature implementation rely on libzip library new version 1.2.0. For now, only build using system library is supported for this new feature, but an update of the bundled library is planed. When everything will be validated, version will be released and merged in php sources (ext/zip), probably in PHP 7.2.
This development is in progress, nothing final, proposed methods still can change.
The tutorial shows how to get the package installed (via a clone of the GitHub repository) and how to work with encrypted archives, creating and reading their contents.