---
title: "Phase 2 never run: shipping the initial zkey"
description: "The circuit-specific phase is initialised from a phase-1 file and the resulting key is deployed without a single phase-2 contribution."
type: "failure-mode"
url: "https://zkpick.com/ceremony/failure-modes/phase-2-never-run-shipping-the-initial-zkey/"
section: "04 Running or reusing a trusted setup"
authors:
  - "MarketComp"
publisher: "MarketComp"
version: "1.3"
updated: "2026-09-12"
license: "CC-BY-4.0"
json: "https://zkpick.com/data/ceremony/failure-modes/phase-2-never-run-shipping-the-initial-zkey.json"
---

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

# Phase 2 never run: shipping the initial zkey

The circuit-specific phase is initialised from a phase-1 file and the resulting key is deployed without a single phase-2 contribution. In that state the verifying key's gamma and delta are both the G2 generator rather than independent secrets, and a prover can cancel the corresponding terms of the verification equation and forge a proof for any statement without a witness. Every other control — a reputable phase 1, a verified transcript, an audited circuit — is satisfied, and the system is still unsound. This is the only setup failure that has produced real losses: in late February 2026 two deployed protocols were drained through exactly this gap, roughly $1.4 million from one and a few thousand dollars from the other, within a week of each other.

**Mitigation:** Treat phase 2 as mandatory for any circuit-specific setup, even a single contribution by the team. Assert in CI and in the deployment checklist that the contribution count is non-zero and that gamma and delta differ from the generator and from each other. Auditors reviewing a Groth16 verifier should check the deployed key for this condition explicitly.