New Techniques for Traitor Tracing: Size 𝑁1/3 and More from Pairings

Abstract

The best existing pairing-based traitor tracing schemes have 𝑂(𝑁‾‾√) -sized parameters, which has stood since 2006. This intuitively seems to be consistent with the fact that pairings allow for degree-2 computations, yielding a quadratic compression.

In this work, we show that this intuition is false by building a traitor tracing scheme from pairings with 𝑂(𝑁‾‾√3) -sized parameters. We additionally give schemes with a variety of parameter size trade-offs, including a scheme with constant-size ciphertexts and public keys (but linear-sized secret keys). We obtain our schemes by developing a number of new traitor tracing techniques, giving the first significant parameter improvements in pairings-based traitor tracing in over a decade.