## CryptoDB

### Paper: New Lattice Two-Stage Sampling Technique and its Applications to Functional Encryption – Stronger Security and Smaller Ciphertexts

Authors: Qiqi Lai , Shaanxi Normal University Feng-Hao Liu , Florida Atlantic University Zhedong Wang , Florida Atlantic University DOI: 10.1007/978-3-030-77870-5_18 (login may be required) Search ePrint Search Google EUROCRYPT 2021 This work proposes a new lattice two-stage sampling technique, generalizing the prior two-stage sampling method of Gentry, Peikert, and Vaikuntanathan (STOC '08). By using our new technique as a key building block, we can significantly improve security and efficiency of the current state of the arts of simulation-based functional encryption. Particularly, our functional encryption achieves $(Q,\poly)$ simulation-based semi-adaptive security that allows arbitrary pre- and post-challenge key queries, and has succinct ciphertexts with only an additive $O(Q)$ overhead. %This significantly improves the current research frontier of simulation-based functional encryption. Additionally, our two-stage sampling technique can derive new feasibilities of indistinguishability-based adaptively-secure $\IB$-$\FE$ for inner products and semi-adaptively-secure $\AB$-$\FE$ for inner products, breaking several technical limitations of the recent work by Abdalla, Catalano, Gay, and Ursu (Asiacrypt '20).
##### BibTeX
@inproceedings{eurocrypt-2021-30813,
title={New Lattice Two-Stage Sampling Technique and its Applications to Functional Encryption – Stronger Security and Smaller Ciphertexts},
publisher={Springer-Verlag},
doi={10.1007/978-3-030-77870-5_18},
author={Qiqi Lai and Feng-Hao Liu and Zhedong Wang},
year=2021
}