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Re: The ability to password protect individual projects

Posted: Wed Mar 07, 2018 1:51 pm
by NotCharlieKaufman
KB wrote:Yes, Katherine and popcornflix have hit the nail on the head. We do get frequent requests to password-protect Scrivener projects, but it's not like password-protecting a single file such as a Word document, which can be encrypted. As Katherine and popcornflix point out, a Scrivener project is not a single file but a folder full of many files. That entire directory would need encrypting, and it would need decrypting on read. That is far from simple. Would each file be decrypted as it was needed? Or would an entire (possibly huge) project directory be encrypted and have to be decrypted as a whole on project open?

This may be worth some more research, as I think this could be easier than you surmise. Pages has the same multi-file package structure as Scrivener and provides transparent encryption by simply packaging as an encrypted ZIP archive.

Files in an encrypted ZIP archive can be listed without the need to decrypt every file, so there is no barrier to Scrivener's existing functionality. Scrivener can ask for the password to an encrypted project upon open, then decrypt individual documents on the fly as they are accessed, fitting with its existing memory management model.

A quick search on Apple's developer site reveals an example app for browsing ZIP archives without unarchiving:

Basically if Scrivener reads its folder structure as a ZIP archive you get encryption for free, and smaller disk footprint. This may also solve your issues with iCloud sync.

Re: The ability to password protect individual projects

Posted: Wed Mar 07, 2018 3:00 pm
by KB
A zipped package would not work for Scrivener at all. Programs that use zip file - such as Pages and Word - are able to do so because they read the entire file into memory and load and write the entire file out to disk on save. Scrivener does not do this, but instead reads each file as it needs it and writes each file inside the package without affecting any other files. This reduces the change of corruption and allows for large projects.

The code you link to is very old and uses deprecated APIs; even so, it could only show the contents of a zip file, not manipulate them on the fly. There are no frameworks or technology on the Mac that allows you to work with files inside a zip file directly. The only way would be to extract a file to a temporary location and write it back into the zip file occasionally, which is not optimal and would break many things in Scrivener. It would also increase the risk of corrupted projects, because a bad write to the zip file could result in a corrupt zip file and thus a lost project, something that could never happen with the current folder structure approach.

Using a zip package is something we have thoroughly explored (the above is just a snapshot of a couple of the problems involved - it goes much deeper) but I'm afraid it is just not a viable option for Scrivener.

All the best,

Re: The ability to password protect individual projects

Posted: Wed Mar 07, 2018 3:37 pm
by NotCharlieKaufman
Well darn. I appreciate the clarification though!