EXEsafe itself can be protected. By selecting 'Protect EXEsafe' under the 'Program' menu, a new window will appear. Ticking the 'Protect EXEsafe' checkbox will allow you to enter a password, up to 31 characters in length. The next time EXEsafe is run, it will ask for the password before entering the program.
To change the password, or disable it, open the 'Protect EXEsafe' window again, and change the password, or untick the checkbox.
Note that this protection is only intended to be an extra obstacle - it does not encrypt EXEsafe. It will stop the majority of undesired people from accessing the program.