Traitor Tracing with Constant Size Ciphertext

Authors: D. Boneh and M. Naor

A traitor tracing system enables a publisher to trace a pirate decryption box to one of the secret keys used to create the box. We present the first traitor tracing system where ciphertext size is "constant," namely independent of the number of users in the system and the collusion bound. A ciphertext in our system consists of only two elements where the length of each element depends only on the security parameter. The down side is that private-key size is quadratic in the collusion bound. Our construction is based on recent constructions for fingerprinting codes.

In proceedings of the 15'th ACM conference on Computer and Communications Security (CCS), pp. 455-470, 2008.

Full paper: pdf         [first posted 2/2008 ]