Ironwood Upgrade: ZEC Supply Verification From Day One

Zcash founder Zooko Wilcox says the proposed Ironwood upgrade will deliver immediate, trustless ZEC supply verification “on Day 1” when running a full node. After the Orchard vulnerability is addressed, the key question in the Zcash community was whether users can verify the circulating supply without relying on developers, auditors, or assumptions. Wilcox argues Ironwood’s goal is not to re-prove whether counterfeit ZEC was ever created in Orchard, but to make the current circulating supply independently verifiable. He writes that users will be able to trustlessly confirm the supply trajectory from the activation block—“16M ZEC now, 21M ZEC eventually”—directly via local validation from their own node. Mechanism: Ironwood prevents the old Orchard pool from continuing private internal circulation. Transactions that would create new outputs in the old pool would be rejected after activation. Funds must pass through Zcash’s “turnstile” accounting, which tracks legitimate inflow vs outflow and blocks attempts to move more ZEC than entered. Wilcox says Ironwood will “snuff out any excess ZEC immediately, trustlessly, and globally,” citing an Orchard legitimacy threshold of about 4.5M ZEC. If no counterfeiting occurred, Ironwood still provides ZEC supply verification by allowing users to prove that no excess supply exists. Over time, migration behavior may also provide evidence: rejected attempts to exit Orchard would indicate counterfeiting. He personally believes there is no counterfeit ZEC, but emphasizes Ironwood removes the need for trust in any individual assessment by enabling ZEC supply verification via the protocol itself.