I was wondering If anyone knew of professional diagram creating software that I can use to create nice looking diagrams for my cyber security research. I tried using gliffy and Visio but they dont have sharp images nor do they have figures such as the "man-in-the-middle" guy. Does anyone have suggestions?
Visio is probably the best. You need to search for additional stencils to add to your Visio library. There are a lot of realistic looking stencils for hardware available for Visio. There are probably security specific stencils somewhere.