Copy protection techniques that utilize a watermark and a permission key
are disclosed. The copy protection techniques can provide single-copy
copy protection in addition to different levels of copy protection. The
permission key and the watermark can also permit the invention to yield
variable levels of copy protection. In one embodiment, content including
a watermark is transmitted to a recipient. The recipient is allowed to
read the content but not record the content unless the recipient
possesses a permission key.