Collusion-Secure Fingerprinting for Digital Data
This paper discusses methods for assigning codewords for the purpose
of fingerprinting digital data (e.g., software, documents, and
images). Fingerprinting consists of uniquely marking and registering
each copy of the data. This marking allows a distributor to detect any
unauthorized copy and trace it back to the user. This threat of
detection will deter users from releasing unauthorized copies.
A problem arises when users collude: For digital data, two different
fingerprinted objects can be compared and the differences between them
detected. Hence, a set of users can collude to detect the location of
the fingerprint. They can then alter the fingerprint to mask their
identities. We present a general fingerprinting solution which is
secure in the context of collusion. In addition, we discuss methods
for distributing fingerprinted data.