One-Way Chain Based Broadcast Encryption Schemes

Abstract

We propose a new broadcast encryption scheme based on the idea of ‘one key per each punctured interval’. Let r be the number of revoked users. In our scheme with p-punctured c-intervals, the transmission overhead is roughly \(\frac{r}{p+1}\) as r grows. Our scheme is very flexible with two parameters p and c. We may take p as large as possible if a user device allows a large key storage, and set c as small as possible if the storage size and the computing power is limited. As variants of the proposed scheme, we further study a combination of a one-way chain and a hierarchical ring. This combination provides a fine-grained trade-off between user storage and transmission overhead. As one specific instance, the combination includes the subset difference (SD) scheme which is considered the most efficient one in the literature.

This work was supported by Samsung Advanced Institute of Technology.