Trisquel:What to type when I set a blank password?

I recently installed trisquel on my computer. When I decided to use the terminal and sudo I was prompted to use a password despite the fact that I set a blank one. I want to know what I am supposed to type then. I am open to going into grub and somehow replacing the password. I have tried out pressing enter at the terminal to no avail. I am the root user and cannot make changes without the password.