Efficient protocols for group key establishment based on secret sharing

Secure group communication is a fundamental requirement in modern distributed systems, relying on efficient and secure group key establishment protocols. While secret sharing has been effectively utilized to construct such protocols, existing approaches often incur significant computational overhead. This paper addresses this efficiency challenge by presenting novel improvements to the group key agreement protocol of Harn and Lin and the group key distribution protocol of Harn and Hsu. Our key insight is to replace the use of Shamir's (n,n) threshold secret sharing scheme in the existing protocols with Shamir's (۲,۲) threshold scheme, which consequently reduces the core polynomial operations from degree n to degree one. This optimization drastically lowers the computational cost associated with polynomial construction and interpolation, while maintaining the security guarantees of the original protocols. Security analysis demonstrates that the proposed protocols provably satisfy essential properties such as key confidentiality, authenticity, and forward secrecy under the hardness of the decisional Diffie-Hellman problem. Performance comparisons confirm that our constructions achieve superior efficiency in both computation and communication, making them highly practical for large-scale group applications.

کلیدواژه ها:

Cryptography ، Group Key Establishment ، Key Agreement ، Key Distribution ، Secret Sharing