A system for protecting commercials included in a digitally distributed
and recorded video that minimizes user's inconveniences resulting from
restrictions imposed on playback of the video. The video is encrypted at
the distributor side and playback of the encrypted video at the user side
is limited in such a way that fast forward and reverse playing is not
performed, and a lower limit is imposed on skip forward and backward so
that only parts of video whose playing time is greater than the time of
typical commercial break can be skipped. This arrangement prevents a user
from selectively skipping commercials without missing pieces of program
itself and thus discourages skipping when the user wants to watch an
entire program, but still enables quick browsing before watching the
entire program as well as moving fast to any part of the program for
watching that part again.