## CryptoDB

### Paper: On Tightly Secure Non-Interactive Key Exchange

Authors: Julia Hesse Dennis Hofheinz Lisa Kohl DOI: 10.1007/978-3-319-96881-0_3 Search ePrint Search Google CRYPTO 2018 We consider the reduction loss of security reductions for non-interactive key exchange (NIKE) schemes. Currently, no tightly secure NIKE schemes exist, and in fact Bader et al. (EUROCRYPT 2016) provide a lower bound (of $\varOmega (n^2)$, where $n$ is the number of parties an adversary interacts with) on the reduction loss for a large class of NIKE schemes.We offer two results: the first NIKE scheme with a reduction loss of $n/2$ that circumvents the lower bound of Bader et al., but is of course still far from tightly secure. Second, we provide a generalization of Bader et al.’s lower bound to a larger class of NIKE schemes (that also covers our NIKE scheme), with an adapted lower bound of $n/2$ on the reduction loss. Hence, in that sense, the reduction for our NIKE scheme is optimal.
##### BibTeX
@inproceedings{crypto-2018-28834,
title={On Tightly Secure Non-Interactive Key Exchange},
booktitle={Advances in Cryptology – CRYPTO 2018},
series={Lecture Notes in Computer Science},
publisher={Springer},
volume={10992},
pages={65-94},
doi={10.1007/978-3-319-96881-0_3},
author={Julia Hesse and Dennis Hofheinz and Lisa Kohl},
year=2018
}