Methods and systems are disclosed in which contact can be safely
distributed and protected in a manner that is viable in terms of
bandwidth economy and ensures that clients can be identified by the
content received. Copies of encrypted content can be provided such that
unique watermarks can be added to the copies. Content can also be both
watermarked uniquely for multiple clients and multicasted to the clients.
As such, content can be distributed using the bandwidth efficiency of
multicasting while providing reliable content protection and
watermarking.