Registration without a phone number on Signal will use zero-knowledge proofs

you have legitimate concerns, but you’re very wrong about this. zero-knowledge proofs are not only the technology behind donation badges and backup payments, but also behind groups. they can’t tie you to a specific donation just like they can’t tie you to a specific group. the great thing about Signal is the client is designed to already not trust the server. in fact you can show that Signal is perfectly safe without even looking at server code.