Xiong (Leo) Fan, Rutgers University

Abstract

In recent years, attribute-based encryption (ABE) and functional encryption (FE) have established themselves as parts of the fundamental primitives in cryptography. The choice of model of computation to represent the functions associated with the functional keys plays a critical role in the complexity of the algorithms of such scheme. Historically, the functions are represented as circuits. However, this results in the decryption time of the ABE and FE schemes growing proportional to not only the worst case running time of the function but also the size of the input, which in many applications can be quite large. In this work, we present the first constructions of a public-key collusion-resistant ABE and FE schemes, where the functions, associated with the keys, are represented as RAMs and the decryption time is proportional only to the actual running time of RAMs.

Joint work with Prabhanjan Ananth, Kai-Min Chung, Elaine Shi and Luowen Qian.