#see vector-im/riot-web#12214

There are some cases where this doesn't happen today, e.g. if you have not verified one of your own devices, all rooms would go red (even large public rooms where you have no intention verifying users).

To make the experience more straightforward, we decided after chatting with @dbkr and @nadonomy to add the additional check that green / red states are only shown if you have verified at least one user in the room. If you haven't, the room is black.

Summary doc on shields: https://docs.google.com/document/d/1RFUN0YRrOs8QZwiblaUbs4wWR0BjA0hBJ27rKJ57Zvk/edit

Checklist for this doc:

User profiles

- [ ] None: e2e off in the room

• Black: Encryption is enabled (I don’t care about their devices)
• Red: I’ve verified them and the other user has an unverified device
• _____ or they were previously verified and their cross-signing identity has changed
• Green: I’ve verified them and all of their devices are verified

Rooms

• None: e2e off in the room
• Black: Encryption is enabled AND no users in the room are verified by current user
• Red: A red user exists in the room AND (at least one user in room verified by current user OR no one else in the room)
• Green: All users are green AND (at least one user in room verified by current user OR no one else in the room)

(Added 2020-02-24) The set of “all users” depends on the type of room:

• For regular / topic rooms, all users including yourself, are considered when decorating a room
• For 1:1 and group DM rooms, all other users (i.e. excluding yourself) are considered when decorating a room

The somewhat complex parenthetical bits above are to avoid a case where you have an unverified device (since “a red user exists” includes yourself) and would have caused black rooms to go red if we didn’t add a check for other verified users.

Messages

• No badge is shown by default
• Warning badge if sent by a user you have verified with an untrusted device
• Warning badge if unencrypted in E2E room

Type of trust to check

• Users: always check cross-signing trust (that’s only kind anyway)

Devices

• For your own devices, check cross-signing trust to ensure other users can trust you easily in the future
• For other users devices, check both cross-signing and legacy device verification, as either is acceptable