why do you want to stop the students from downloading or saving the content? I would think this would be useful for revision or if they were unable to get online for day.
one way I could think of would be to open the media in a popup and disable the toolbars and right clicks using javascript?? not sure if this would help you.
It is quite easy to download a SWF file just view the source and can get it easily.
but do some research on streaming, its not as hard as it seems. No matter what you do unless you are streaming a local copy of the file whether it be movie, audio or swf will be stored in the temp folder