Paper 2026/2112

Mist: Transparent Polynomial Commitments from Class Group Subset-Product Accumulators

Sriram Sridhar, University of California, Berkeley
Abstract

We construct the first polynomial commitment in groups of unknown order that simultaneously requires no trusted setup, has quasilinear prover time, and has constant-size opening proofs. Our main technical contribution is a transparent class group realization of the subset-product accumulator relation introduced by Morphic accumulators (CRYPTO ’26). It supports accumulating a fixed family of class group elements and proving prescribed algebraic relations among the accumulated elements, yielding constant-size range arguments with quasilinear prover time. Combining these range proofs with the DewTwo framework (CRYPTO ’25) gives the first transparent polynomial commitment with quasilinear prover time and constant-size openings. Concretely, our construction also gives the shortest known opening proofs (1.3 KB) among transparent polynomial commitments. We prove security under falsifiable class group assumptions and also develop new extraction techniques over dyadic rationals, which may be of independent interest.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
Keywords
SNARKPolynomial Commitment SchemeGroups of Unknown Order
Contact author(s)
srirams @ berkeley edu
History
2026-09-22: approved
2026-09-19: received
See all versions
Short URL
https://ia.cr/2026/2112
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2026/2112,
      author = {Sriram Sridhar},
      title = {Mist: Transparent Polynomial Commitments from Class Group Subset-Product Accumulators},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/2112},
      year = {2026},
      url = {https://eprint.iacr.org/2026/2112}
}
Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content.