A system and method for enabling broadcast programs to be copied once only
by consumer recorders includes writing a unique media identification on
each blank disk to which content is to copied in a read-only area of the
disk before it is initially recorded. Also, a one-way key management
media key block is written to the disk. A content key is derived by
combining a media key, derived from the media key block, with the media
identification. Additionally, to facilitate copying the content one time
only, an exchange key is established between the recorder and a sender
such as a satellite receiver or a disk player that is associated with the
recorder, and the exchange key is modified with one or more special
numbers representing control commands including copy once and copy no
more. The modified exchange key is then encrypted using the content key
to render an encrypted modified exchange key, and the encrypted modified
exchange key is then hashed with a nonce to render a bus content key. The
bus content key is then used to encrypt the data for copying the data to
a disk. Unauthorized attempts to copy the data after the first authorized
copy has been made cannot succeed because the media ID is different on
subsequent blank media. Further, if illegal clones are manufactured that
can calculate the media key, new blank media can change the media key
block such that the clones can no longer calculate the correct media key.
Authorized players, however, can decrypt the data to display it.