Distributed Monotone-Policy Encryption for DNFs from Lattices

Paper 2026/318

Distributed Monotone-Policy Encryption for DNFs from Lattices

Jeffrey Champion, The University of Texas at Austin

David J. Wu, The University of Texas at Austin

Abstract

Distributed monotone-policy encryption augments public-key encryption with fine-grained decryption capabilities in a trustless manner. In this scheme, users independently generate a public/private key-pair and post their public key to a public-key directory. Thereafter, anyone can encrypt a message to a set of public keys together with an access policy. Any set of users that satisfies the access policy can decrypt the ciphertext while the message should remain computationally hidden to any unsatisfying set of users. The primary efficiency requirement is succinctness: namely, the size of the ciphertext should be sublinear (or polylogarithmic) in the description length of the policy. Distributed monotone-policy encryption directly generalizes recent trustless cryptographic notions like threshold encryption with silent setup and distributed broadcast encryption. In this work, we show how to construct distributed monotone-policy encryption for Boolean formulas in disjunctive normal form (DNF formulas) that supports an unbounded number of users. Security relies on the decomposed learning with errors (LWE) assumption, a simple and falsifiable lattice assumption, in the random oracle model. Previously, such a scheme was only known from plain witness encryption in the random oracle model. Our scheme has a transparent setup and the ciphertext size is $\mathsf{poly}(\lambda, \log N)$, where $N$ is the number of variables in the DNF formula.

Note: Added paragraph on independent work.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: A major revision of an IACR publication in EUROCRYPT 2026
Keywords: lattices decomposed LWE succinct LWE silent setup threshold encryption
Contact author(s): jchampion @ utexas edu
dwu4 @ cs utexas edu
History: 2026-02-24: revised; 2026-02-19: received; See all versions
Short URL: https://ia.cr/2026/318
License: CC BY

BibTeX

@misc{cryptoeprint:2026/318,
      author = {Jeffrey Champion and David J. Wu},
      title = {Distributed Monotone-Policy Encryption for {DNFs} from Lattices},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/318},
      year = {2026},
      url = {https://eprint.iacr.org/2026/318}
}