Verifying device does not synchronize master key to the verified device

[eras]

Steps to reproduce

1. I have a Element Web that shows the following information in the Cross Signing settings:

2. I pressed the "Verify this session" button

3. I verified the session on an Element Android 1.6.28.

On the mobile phone app Security & Privacy/Cross-Signing. "Private Keys on device" and then "Master Key: ... User Key: ... Self Signed Key: ..." show that the device has access to the master key.

Outcome

What did you expect?

I expected the master key to arrive to the verified device.

What happened instead?

However, this view still shows "Master private key" "not found locally"

Operating system

Windows 10, 23H2

Browser information

FireFox 134.0.2

URL for webapp

https://app.element.io/

Application version

Element Web 1.11.91, Crypto version: Rust SDK 0.8.0 (21f7cc7), Vodozemac 0.8.1

Homeserver

matrix.org

Will you send logs?

Yes

[eras]

Alas it was not possible to submit the logs, as submitting the logs issued the error message "Failed to send logs: IDBDatabase.transaction: 'logs' is not a known object store name".

[BillCarsonFr]

On the mobile phone app Security & Privacy/Cross-Signing. "Private Keys on device" and then "Master Key: ... User Key: ... Self Signed Key: ..." show that the device has access to the master key.

On android Private Keys on device means that this device can cross-sign new devices, i.e that it has SSK and USK private part. But it might not have the private MSK

The other keys on screen are the public parts

[richvdh]

Closing in favour of element-hq/element-android#8994.

Sorry @eras, looks like your private master key has gone missing, and if you don't have the recovery key, the only option is to do a reset.