A study room that stays on your computer

What can leave your computer, and only when you use it:

• Book and article search sends the ISBN, DOI or words you type to Open Library, Crossref and (if you saved a key) Google Books or ISBNdb. Only when you press Search, or drop a book file that names its ISBN (this can be turned off).
• Cover pictures are loaded from the cover sites when search results show them. Turn covers off and none is loaded.
• Reading a scanned book (OCR) downloads each language’s reading data once from jsDelivr, the first time you use it. The pages are read on your computer and never sent.
• The AI tab is off by default. With a model on your own computer, nothing leaves it. With an online service you choose and give a key to, the text it needs to answer does go to that service.
• Your phone is off by default. Turn it on and pair a phone, and that phone opens Voynich on your computer over your own Wi-Fi (or Tailscale), with nothing in between.
• Writing together live is off until you share a document: then that one document goes to the browser of whoever opens its link, over your own network or Tailscale, and nowhere else.
• A study circle is off until you make or join one: then your Voynich finds the other members through a public directory and connects to them directly, encrypted. They see your name in it, who is in it and who is online, and each other’s internet addresses; and, only for the rooms you choose to share with that circle, each day’s study minutes and flashcard answers and your streak, the decks you choose to share (without your progress), your page in a book you read together (its details, never the book), and the messages you write in its chat. Nothing else of yours.
• Sync between your own computers is off until you start it: then your other computers that join with its invite get a copy of your notes, books, cards and the rest, directly and encrypted, and nobody else does.
• Updates ask GitHub for one small file when you press Check now, or once a day if you turn that on. They carry only the program’s name and version.

There are no analytics, crash reports or advertising, and the program only answers to your own computer (and to phones you pair yourself, if you turn that on; a circle’s members reach only the circle’s own small program, never Voynich). Inside Voynich, Settings, Privacy lists all of this again with your own settings, and it is checked against the program’s code by a test.