A hybrid traitor-tracing enabling system comprises an inner code and a
multi-level outer code. The inner code comprises encrypted tables
comprising codewords for file segment variations. One level of the
multi-level outer code comprises assignments of a cluster of sequence
keys to manufacturers or models of media players. Another level comprises
assignments to the media players of sequence keys within the cluster. The
system enables tracing of only a manufacturer or model, or a
manufacturer, model, and a media player. When tracing a manufacturer or
model, the system enables detection with relatively few recovered files.
With additional recovered files, the media player used for piracy can be
discovered. Furthermore, the present system enables detection of
collusion between manufacturers or models and collusion between
individual media players.