Add "Setup secure backup" to user onboarding tasks

[estellecomment]

Your use case

What would you like to do?

Nudge users to setup secure backup, every where we can !

Why would you like to do it?

Secure storage is crucial to solving the problem of lost messages on logout (or session cookie loss, or change of device), which is still our number 1 user problem in Tchap (Tchap is a fork of element).

How would you like to achieve it?

Add "Setup secure Backup" to user onboarding tasks. (see mock UI below)
"Set up Secure Backup" button would trigger the flow of dialogs that already exist for secure backup setup.

Have you considered any alternatives?

Forcing users to set up secure storage, for example with "secure_backup_required": true (see doc : https://github.com/vector-im/element-web/blob/develop/docs/e2ee.md#requiring-secure-backup).

This is not helpful because users forced into the secure backup setup flow without their consent are annoyed, don't read the dialogs, and don't store their security key. They end up with a secure backup without a key, which is not helpful to recover their lost messages.

Additional context

Proposed draft UI (ignore the weird spacing) :

This is up to discussion, for example :

• what language to use so people understand that it's useful ?
• 6 steps, is that too many steps ? We risk information overload which would make this page bother people instead of help them. (Tchap uses UseCase.WorkMessaging, I'm less familiar with other cases)
• in what order should we display this new step ? (I have no opinion. :) )

[estellecomment]

Tchap can provide dev time to do this in element-web.
We will most likely do it in our fork anyway, so we would rather do it in element-web, it would be easier to maintain for us.

[MarcWadai]

Hi, we are going to work and implement this, is this something you guys are still interested ? Or are you planning to change how things are going to work on the onboarding steps ?