An Efficient Leakage-Resilient Authenticated Group Key Exchange Protocol

Abstract

Leakage-resilient (LR) cryptography including LR authenticated key exchange has been extensively studied in recent years. However, there is few literature to model and construct LR authenticated group key exchange (AGKE) protocol, which is the most practical cryptographic primitive for the group communication applications. In this paper, we first introduce an λ-bounded after-the-fact LR (λ-BAFLR) CK security model to assess the security of AGKE protocols in the leakage environments. Then by appropriately combining Diffie-Hellman (DH) group key exchange protocol and public key encryption with the security against adaptively chosen plaintext after-the-fact leakage attacks, we propose the first LR AGKE protocol, and show a formal proof of the λ-BAFLR CK security in the standard model based on the game simulation techniques. Our result shows that the proposed AGKE protocol attains the property of LR without incurring additional communication and computation cost by comparing with the related non-LR schemes.