[YYS25] Fully Homomorphic Encryption with Chosen-Ciphertext Security from LWE

Authors: Rupeng Yang, Zuoxia Yu, Willy Susilo | Venue: CRYPTO 2025 | Source

Abstract

We construct (1-hop) fully homomorphic encryption (FHE) schemes with chosen-ciphertext (CCA) security from the learning with errors (LWE) assumption in the standard model. Security of our construction only relies on the circular-secure LWE, which matches the assumptions needed for FHE with the basic chosen-plaintext security. Besides, the scheme achieves a security notion that is strictly stronger than the CCA1 security. Prior FHE schemes with even just CCA1 security require either the random oracle model or non-falsifiable assumptions. The construction follows the well-known Naor-Yung double encryption paradigm. However, unlike previous works [Boneh et al., ITCS 2012; Canetti et al., PKC 2017; Manulis and Nguyen, Eurocrypt 2024], which employ general zero-knowledge succinct non-interactive arguments of knowledge (ZK-SNARKs), we design a special succinct argument to prove the validity of FHE ciphertexts. The succinct argument is constructed from batch arguments for NP and a new primitive called predicate extractable commitment, which may be of independent interest.

BibTeX

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@Inproceedings{C:YanYuSus25,
  author = {Rupeng Yang and Zuoxia Yu and Willy Susilo},
  title = {Fully Homomorphic Encryption with Chosen-Ciphertext Security from {LWE}},
  pages = {371--405},
  editor = {Yael Tauman Kalai and Seny F. Kamara},
  booktitle = {Advances in Cryptology -- {CRYPTO}~2025, Part~III},
  volume = {16002},
  series = {Lecture Notes in Computer Science},
  address = {Santa Barbara, CA, USA},
  month = {aug~17--21},
  publisher = {Springer, Cham, Switzerland},
  year = {2025},
  doi = {10.1007/978-3-032-01881-6_12},
}