keyboard shortcuts for Adobe Flash Player

Flash Player isn't a video player.  You can write a video player using Flash technology, but we're a low-level technology that's providing the nuts and bolts. 

Decisions about what, if any keyboard shortcuts get implemented are left to the developer of the specific video player embedded on the page that you're looking at.

Spacebar is a pretty popular way to let people pause from the keyboard, so if the video player has focus (it was the last thing you clicked on), it may or may not pause, but that's a pretty reasonable convention for a developer to implement at this point.