I asked about this years ago, I think it was PairNic. They said file a legal document and send them a copy. So, there's the technical route, whoever has the pa

I asked about this years ago, I think it was PairNic. They said file a legal document and send them a copy. So, there's the technical route, whoever has the passwords wins. But if it matters, and you don't want your technical heirs to be fighting each other, you should probably establish ownership and succession with a lawyer.