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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
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DOI: 10.1007/978-3-030-77870-5_18 (login may be required)
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Conference: EUROCRYPT 2021
Abstract: 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).
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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
}