Efficient Revocable Certificateless Encryption Secure in the Standard Model

Certificateless encryption (CLE) effectively solves the inherent key escrow problem in identity-based encryption while retaining its keeping certificate-free property. Although a number of CLE schemes have been available in the literature, little attention has been paid to the problem of user revocation in the certificateless setting. In this work, we study CLE systems with user revocation capabilities. At first, we establish reasonable security models for revocable CLE (RCLE) schemes. Then we put forward the first efficient and CCA2-secure RCLE scheme in the standard model. A rigorous security proof of our RCLE scheme is presented based on the decisional truncated q-ABDHE assumption and decisional bilinear Diffie-Hellman (DBDH) assumption.