If you really want to run a masternode although you aren't too much into the security stuff (which I advise against!) then you at least might wanna use 2-FA for your SSH access.

Here's a fool-proof (well, there's always a greater fool!) tutorial on how to do that on Ubuntu. http://www.howtogeek.com/121650/how-to-secure-ssh-with-google-authenticators-two-factor-authentication/


edit: btw, the Android Google Authenticator isn't open source anymore! You can download "OTP Authenticator" which is a fork of the last Google Authenticator version that was open source. There's the binaries on the play store, the source is hosted on sourceforge iirc.