A2BE: Accountable Attribute-Based Encryption for Abuse Free Access Control

As a recently proposed public key primitive, Attribute-Based Encryption (ABE) (including Ciphertext-Policy ABE (CP-ABE) and Key-Policy ABE (KP-ABE)) is a highly promising tool for secure fine-grained access control. For the purpose of secure access control, there is, however, still one critical functionality missing in the existing ABE schemes, which is the prevention of key abuse. In particular, two kinds of key abuse problems are considered in this paper, illegal key sharing among colluding users and misbehavior of the semi-trusted attribute authority including illegal key (re-)distribution.