If they imported the app directly with a USB cable, it might not have been necessary to change the safety number for the device because the provenance of the ke

If they imported the app directly with a USB cable, it might not have been necessary to change the safety number for the device because the provenance of the key was intact. The safety number isn't about the physical device, it's derived from key material (which is why someone can message you from the desktop app without seeing the safety number change). From the docs: > The most common scenarios where a safety number advisory is displayed are when a contact switches to a new phone or re-installs Signal, but these actions don't always result in a safety number change. I don't think there's any reason to assume the security or privacy of Signal is in question here, especially since it's one of the few apps that has been extensively studied.