A strongly secure and efficient certificateless authenticated asymmetric group key agreement protocol

In Eurocrypt’2009, Wu et al. (2009) presented an important primitive named the asymmetric group key agreement (AGKA) protocol. In such a primitive, a group of users generate a common public encryption key, and each user only holds his own secret decryption key. Authenticated asymmetric group key agreement (AAGKA) protocols are a kind of AGKA protocol that can be secure against active attacks. AAGKA protocols in certificateless public key cryptography (CL-PKC) have some preponderance than those in identity-based cryptography and PKI cryptography. However, existing AAGKA protocols in CL-PKC only consider security against normal type adversaries, the weakest adversaries considered in CL-PKC literature. To solve this problem, an improved security model that considers security against super adversaries and a provably secure certificateless AAGKA protocol under the improved security model are proposed. Efficiency comparison shows that the proposed protocol is more efficient. © 2018 Totem Publisher, Inc. All rights reserved.