I'm working on a project to setup a secure system to share files between 5 Windows computers. The computers are part of a domain so could have multiple different users logging in (based on an AD group). The files would contain bank/account information. It is possible to setup a server using re-purposed hardware.
I've looked at NFS or Samba, but it doesn't look like I would be able to encrypt the data in transit without additional setup (like VPN). Other options I've found so far are Syncthing or Unison. The advantage of sync would be each computer has a copy in case something breaks.
Any suggestions on how I could get this working?