This. If you can just trust the clients, lots of things get easier. Though even then distributed systems are not trivial -- just look at Lustre (where clients

This. If you can just trust the clients, lots of things get easier. Though even then distributed systems are not trivial -- just look at Lustre (where clients in a cluster are all trusted, and if you don't trust some client, then it must use a proxy such as an NFS server running on a cluster member client).