Paper 2026/2810
QUASI: Post-Quantum Quorum Attestation of Pre-Validated Statements
, University of California, Santa BarbaraAbstract
We present QUASI, a newly conceived class of protocols that enable a group of parties to produce a publicly verifiable attestation about a pre-validated statement. Designed for quorum-based systems, QUASI enables parties to attest to external entities that the statement is valid. Surprisingly, each party need not sign the entire statement: authenticating only a small subset of symbols suffices for the quorum to attest to the whole. A simple deterministic construction illustrates this possibility. Built purely from hashing and error correction, QUASI achieves small per-party contributions and low attestation generation and verification costs, without relying on SNARKs for aggregation. Our main contribution is a randomized construction achieving reductions of more than $10\times$ in per-party contribution size and hash computations for generation and verification, compared with full hash-based signatures. QUASI is a generic primitive supporting diverse applications. Two principal use cases are external attestation for signature-free consensus, enabling clients to verify statements about committed state; and preprocessing for SNARK-based aggregation, compounding QUASI's savings with succinct-proof compression.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- Preprint.
- Keywords
- post-quantum cryptographyhash-based authenticationfault tolerance
- Contact author(s)
-
maksym @ ucsb edu
dahliamalkhi @ gmail com - History
- 2026-11-10: approved
- 2026-11-07: received
- See all versions
- Short URL
- https://ia.cr/2026/2810
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2026/2810,
author = {Maksym Ioffe and Dahlia Malkhi},
title = {{QUASI}: Post-Quantum Quorum Attestation of Pre-Validated Statements},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/2810},
year = {2026},
url = {https://eprint.iacr.org/2026/2810}
}
