Fingerprinting and traceability codes are used for copyright protection of 
licensed content. To prevent unauthorized redistribution, each legal copy 
is supplied with an imperceptible user-identifying signature (fingerprint) 
which is a codeword of a fingerprinting (or traceability) code.

We introduce the notion of two-level fingerprinting and traceability 
codes. In this setting, the users are organized in a hierarchical manner by 
classifying them into various groups; for instance, by dividing the 
distribution area of the content into several geographic regions, and 
collecting users from the same region into one group. The two-level codes 
we propose have the following property: If a coalition of at most t users 
attempts to modify the fingerprints and create an illegal copy, the decoder 
can identify at least one of the guilty users. For coalitions of size 
greater than t, but smaller than some value s, the decoder is capable of 
identifying a group that contains a member of the coalition.

In this work, we provide constructions for two-level fingerprinting codes 
and characterize achievable rates. We also obtain sufficient conditions for 
two-level traceability codes.