## Cryptology ePrint Archive: Report 2015/453

An Optimization of Gu Map-1

Yupu Hu and Huiwen Jia

Abstract: As a modified version of GGH map, Gu map-1 was successful in constructing multi-party key exchange (MPKE). In this short paper we present a result about the parameter setting of Gu map-1, therefore we can reduce a key parameter $\tau$ from original $O(n^{2})$ down to $O(\lambda n)$ (in theoretically secure case, where $\lambda$ is the security parameter), and even down to $O(2n)$ (in computationally secure case). Such optimization greatly reduces the size of the map.

Category / Keywords: Multilinear maps, GGH map, Gu map-1, Multi-party key exchange (MPKE), Lattice based cryptography.