riot.im/app -> app.element.io required manual key restore and should not

[caev]

Screenshot 2020-07-17 at 12 10 18

Description

I followed the nag-bars to move from riot.im/app to element.io and ended up in a state where historical messages didn't decrypt. The key backup feature is supposed to undo perfect forward secrecy but didn't do that.

Steps to reproduce

• sign in to element.io with matrix server password
• confirm element.io sign-in with riot.im/app session
• pair the sessions by comparing emoticons
• dig into security settings and verify that key backups are working. They are.
• log out of riot.im/app

Expected behaviour:

• all past received messages decrypt
• all past sent messages remain marked secure (they don't. separate bug,)

Actual behavior:

• past received messages initially don't decrypt and offer "request key from other devices" link. The other device is gone; I signed out of it. The link is a suboptimal stop-gap because it doesn't transfer all keys. It requests them one at a time. How do I know when it's safe to get rid of the other device?
• I press "restore backup" in the screenshot. No password is requested. The backup is restored.
• now past messages decrypt, and the problem is solved.

Backups should be automatically restored as part of the cross-signing "pairing a new device" wizard.

Version information

• Platform: web (in-browser)

For the web app:

• Browser: Chrome 83.0.4103.119
• OS: Chrome OS
• URL: element.io Element version: 1.7.1 / olm version: 3.1.3

[ghost]

I also have issues with this.