Constant-Round Group Key Exchange from the Ring-LWE Assumption

Published: July 14, 2019


Daniel C. Apon, Dana Dachman-Soled, Huijing Gong, Jonathan Katz


Group key-exchange protocols allow a set of N parties to agree on a shared, secret key by communicating over a public network. A number of solutions to this problem have been proposed over the years, mostly based on variants of Diffie-Hellman (two-party) key exchange; to the best of our knowledge, however, there has been almost no work looking at candidate post-quantum group key-exchange protocols. Here, we propose a constant-round, scalable protocol for unauthenticated group key exchange (i.e., with security against a passive eavesdropper) based on the hardness of the Ring-LWE problem. By applying the Katz-Yung compiler using any post-quantum signature scheme, we obtain a (scalable) protocol for authenticated group key exchange with post-quantum security. Our protocol is constructed by generalizing the Burmester-Desmedt protocol to the Ring-LWE setting, which requires addressing several technical challenges.
Proceedings Title: The Tenth International Conference on Post-Quantum Cryptography
Volume: 11505
Conference Dates: May 8-10, 2019
Conference Location: Chongqing, -1
Conference Title: n/a
Pub Type: Conferences


Ring Learning With Errors, Group Key-Exchange
Created July 14, 2019, Updated September 11, 2019