---
title: "Buying post-quantum security you do not have"
description: "A hash-based system is chosen for post-quantum posture, but the deployed system wraps into a pairing SNARK, or the zero-knowledge property is only…"
type: "failure-mode"
url: "https://zkpick.com/proof-systems/failure-modes/buying-post-quantum-security-you-do-not-have/"
section: "01 Choosing a proof system"
authors:
  - "MarketComp"
publisher: "MarketComp"
version: "1.3"
updated: "2026-09-12"
license: "CC-BY-4.0"
json: "https://zkpick.com/data/proof-systems/failure-modes/buying-post-quantum-security-you-do-not-have.json"
---

*By MarketComp. Updated 2026-09-12. Version 1.3. CC BY 4.0.*

# Buying post-quantum security you do not have

A hash-based system is chosen for post-quantum posture, but the deployed system wraps into a pairing SNARK, or the zero-knowledge property is only computational, or the surrounding signatures and key exchange remain classical. The property does not compose the way the decision assumed.

**Mitigation:** Separate soundness from confidentiality and check each end to end. If a long-lived secret is hidden, the hiding property must itself be statistical or post-quantum — a hash-based proof system does not supply that by itself.