They can use your phone number as an identifier to track when youve sent encrypted messages to someone else on signal. They can't read it from the servers.
If Tucker was infected with that expensive phone vulnerability that the NSA uses (starts with a P) then they could remote log in to the phone and read his messages that way. If I'm not mistaken, Graphene OS fixes that vulnerability but if youre using out of box Android or iOS then youre toast. He is probably not using custom OS for his phone.
I've already read up all on signal.
They can use your phone number as an identifier to track when youve sent encrypted messages to someone else on signal. They can't read it from the servers.
If Tucker was infected with that expensive phone vulnerability that the NSA uses (starts with a P) then they could remote log in to the phone and read his messages that way. If I'm not mistaken, Graphene OS fixes that vulnerability but if youre using out of box Android or iOS then youre toast. He is probably not using custom OS for his phone.