Watermarking identification for private and public users: the broadcast channel approach

In this work we study the problem of identification via the degraded broadcast channel with random parameters. Inner and outer bounds are derived on the identification capacity region when the random parameters are known non-causally to the encoder and to the non-degraded decoder. Applications to watermarking are suggested. In particular, this model describes the situation when watermarks are supposed to be identified by both private and public users.