I remember the last time I really cared to look into this was in the 2000’s, I had these wdtv embedded boxes that had a super anemic cpu that doing local copies with scp was slow as hell from the cipher overhead. I believe at the time it was possible to disable ciphers in scp but it was still slower than smbfs. NFS was to be avoided as wifi was shit then and losing connection meant risking system locking up. This of course was local LAN so I did not really care about encryption.
It's still possible but we only suggest doing it on private known secure networks or when it's data you don't care about. Authentication is still fully encrypted - we just rekey post authentication with a null cipher.
- IF you don't trust it
- AND you want to use it
=> run it on a private network
You don't have to trust it for security to use it. Putting services on secure networks when the public doesn't need access is standard practice.