Paper 2025/1650 Original: eprint.iacr.org/2025/1650 ↗

WISCH: Efficient data signing via correlated signatures

Abstract

We present WISCH, a commit-reveal protocol that combines compact aggregate signatures with hash-based commitments to enable selective disclosure of correlated data in multiparty computation. The protocol separates an on-chain verification core from off chain preparation, so that verification cost depends only on the number of openings, not on the size of the underlying message space. This yields asymptotic efficiency: on-chain cost grows linearly in the number of revealed items and is independent of the ambient domain, while the per-byte overhead decreases with the message granularity. Security is established via a simulation-based proof in a UC framework with an ideal ledger functionality, in the algebraic group and global random-oracle models, under standard assumptions for discrete-log-based signatures and hash-based commitments. Thus WISCH provides selectively verifiable revelation with succinct on-chain checks and provable security guarantees.