SIT: Supersingular Isogeny Tree-based Group Key Exchange
Hector B. Hougaard, Atsuko Miyaji · 2020
We present the first constant-round, tree-based, group key exchange protocol based on SIDH with logarithmic communication and memory complexity, where the only previous isogeny-based group key exchanges have linear communication and memory complexity. We show that our protocol satisfies post-quantum security through a reduction to the Supersingular Decisional Diffie-Hellman (SSDDH) problem in the G-CK(plus) security model.