Disable openSSH data encryption

If you have 2 PCs connected through an internal & private LAN and run e.g. backups between them using rsync or just copy files using scp and the file transfers are too slow because of the CPU usage of openssh to en/decrypt the data in transit then you could take into consideration to disable the data encryption (if the data you're transferring isn't too secret).

If you opt for that you can enable the "none" cipher as follows:

  • on the target host which runs the "sshd" daemon edit its "sshd_config" and set the parameter "NoneEnabled yes" and restart the sshd daemon.
  • on the source host which connects to the target use...
    ssh -oNoneEnabled=yes -oNoneSwitch=yes
    scp -oNoneEnabled=yes -oNoneSwitch=yes <yourfile(s)> :
    rsync -e "ssh -oNoneEnabled=yes -oNoneSwitch=yes"
    The two parameters will disable data encryption for the data in transit (but the authentication and encryption for console-traffic will still be in place).
    Just remember not to do it when your data goes through the Internet or insecure parts of your LAN.