Authenticated key agreement for blockchain-based WBAN

Certificateless authenticated key agreement (CLAKA) is important to prevent the escrow problem. It also mitigates the certificate management burden in storage and during the message exchange. However, many previously designed CLAKA protocols were designed in the centralized system architectures that may cause the single point of failure. A new CLAKA is designed in a decentralized (blockchain) architecture that is very suitable for wireless body area networks (WBANs). The proposed protocol is secure as long as it computes a common session key between WBAN user and blockchain nodes. An ID-based blind signature with message recovery is used between blockchain nodes. The blind signature with message recovery is used to achieve authentication and anonymity by acquiring a signature without disclosing the message. It also has advantage in minimizing the size of signature and it is efficient in a situation of limited bandwidth. The protocol analysis shows that it is secure and can resist many WBAN security attacks compared to the existing authenticated key agreement protocols.