Pairing Free Certified Common Asymmetric Group Key Agreement Protocol for Data Sharing Among Users with Different Access Rights

Research into a pandemic like Covid-19 needs a tremendous input of patient histories and characteristics. Patients and doctors are only willing to share these sensitive data when they are ensured that the data are solely used by legitimate research laboratories. Asymmetric group key agreement (AGKA) protocols provide a good cryptographic primitive to address this requirement. The AGKA protocols proposed in literature provide users with a common public group key and a different decryption key by relying on compute intensive pairing operations. In this paper, we propose a new primitive, called the Common AGKA (CAGKA) protocol in which the users share the same private-public key pair, resulting in a more efficient solution. By combining Elliptic Curve Qu Vanstone certificates and a recently proposed Canetti–Krawczyk (CK) secure mutual authentication protocol, a one round self-certified pairing free CAGKA protocol is defined, which can be also globally certified after one additional round.