Title:An Efficient Certificateless Proxy Re-Encryption Scheme without Pairing
Speaker: Arinjitha Paul (IIT Madras)
Details :Fri, Sep 15, 2017 11:00 AM, @ Turing Hall
Abstract:Proxy re-encryption (PRE) is a cryptographic primitive introduced by Blaze, Bleumer and Strauss to provide delegation of decryption rights. PRE allows re-encryption of a ciphertext intended for Alice to a ciphertext for Bob via a semi-honest proxy, who should not learn anything about the underlying message. In 2003, Al-Riyami and Patterson introduced the notion of certificateless public key cryptography which offers the advantage of identity-based cryptography without suffering from the key escrow problem. The existing certificateless PRE (CLPRE) schemes rely on costly bilinear pairing operations. In ACM ASIA-CCS SCC 2015, Srinivasan et al. proposed the first construction of a certificateless PRE scheme without resorting to pairing in the random oracle model. However, in this work, we demonstrate a flaw in the CCA-security proof of their scheme. Also, we present the first construction of a CLPRE scheme without pairing which meets CCA security under the computational Diffie-Hellman hardness assumption in the random oracle model.

This is joint work with S.Sharmila Deva Selvi and C. Pandu Rangan, and is accepted at Eleventh International Conference on Provable Security (ProvSec 2017).