What Mark said is the true facts and we'll never get around that.
A solution from Apple called HLS is interesting in how it breaks up the files for adaptive streaming.
It has some security options that (1) prevent the files from being pulled for your CDN to other sites (much like htaccess can work for JPG hotlinking) and (2) some of their own encryption using https keys that also works to secure the video in a subscriber area.
Those two things "help", but eventually the stream is on the viewers computer and somebody will make a recorder to capture it.
Side benefit is that it is not just a file ended in .mp4. Its a series of tiny files (4 to 10 seconds each) so the simple right click to save doesn't currently work.
Also, at this time, not all players work with it - which limits the sites that can rip and use. JWPlayer, only the $299 yearly option works, others it takes a $250 plug-in.
HTML5 will play it with the video tag in Safari, but its not fully ready in other browsers yet.
More Details:
https://developer.apple.com/streaming/