Why a block asks before it runs

This page is for anyone opening a folder of documents: what a block is allowed to do, why Plicine asks before running one, and what your answer means.

Why blocks need a yes from you

A vault is a shared folder. Add-on blocks are small programs, and anything in that folder could have been put there by someone other than the person who wrote the document you're reading, or changed since you last looked. Plicine treats blocks the way a careful person treats macros in a spreadsheet someone emailed them: nothing runs until you say so, on your own computer.

The blocks that come with Plicine (the table of contents, images, callouts, cards and columns) are part of the app and never ask.

What the panel asks

When a document uses an add-on block this computer hasn't seen, a panel appears above it: "This document wants to run a block". It names the block, says where it came from and says what it's asking for, either "No network or storage access" or a plain list of what it wants. You choose Run or Don't run. With several blocks waiting there's also Run all.

Your answer is recorded against the block's exact contents, not its name. If the block is changed afterwards, even by one character, Plicine asks again, and the panel tells you when it's an update of something you said yes to before ("updating 1.0.0 which you approved before"), so you know it isn't the same code.

Your answer also stays on your computer. It isn't saved in the shared folder, which means:

• Saying yes doesn't say yes for anyone else who opens the same folder. Each person makes their own call.
• If you open the same folder on a second computer, you're asked again there.

Sharing a folder covers what this looks like for a team.

What a block can and can't do

Every block says in advance whether it wants two things: the internet, and somewhere to save data. Both are off unless the block asks and you agree.

A block you've said yes to still runs in a sealed box (a sandbox). It can't see your files, it doesn't know where your folder is, and it can't read another block's data. Without the internet permission it can't contact anything at all. Without the saving permission it has nowhere to keep anything, so nothing it does lasts between visits. A block that's allowed to save keeps a small amount of data on your computer, apart from the shared folder.

What "Don't run" does

Don't run blocks that exact block on this computer. The document shows a plain placeholder where it would have been. Blocked blocks stay listed under the panel, folded away ("1 block is blocked on this machine"), with an Allow button for when you change your mind.

What to say yes to

Run the blocks you expect to see in a document, from people you trust. A block you didn't expect is one to leave on Don't run until you've asked whoever shares the folder.

For technical readers: Security sets out what's protected, from whom, and how.