False shares in verifiable secret sharing with finite field commitments

TL;DR

This paper identifies a vulnerability in finite field-based verifiable secret sharing schemes, where false shares can be fabricated to disrupt secret reconstruction, highlighting a security flaw in existing protocols.

Contribution

It introduces a method to fabricate false shares in VSS schemes with finite field commitments, exposing a new security vulnerability.

Findings

False shares can be fabricated to prevent secret reconstruction

Vulnerability affects schemes with finite field commitments

Security of certain VSS protocols is compromised

Abstract

Verifiable secret sharing (VSS) is designed to allow parties to collaborate to keep secrets. We describe here a method of fabricating false secret shares that appear to other parties to be legitimate, which can prevent assembly of the decryption key. This vulnerability affects VSS schemes using verification commitments bounded to a finite field.