Zcash Locks the Orchard on Tuesday — Turns Out Your IP Was the Bigger Leak

Zcash will activate the Ironwood upgrade at block 3,428,143 on Tuesday, permanently closing off the Orchard pool to inbound transfers and allowing only one-way withdrawals from the shielded address users already hold. The pool currently holds 3.76 million ZEC, valued at roughly $1.89 billion, or about 22% of circulating supply. Developers said existing balances remain safe and that most holders do not need to take action on activation day. Wallet providers are still building migration tools, and some exchanges may pause deposits or withdrawals during the switchover, which developers attributed to integration delays rather than any protocol malfunction.

The upgrade introduces a one-way "turnstile" mechanism that tracks the total amount of ZEC entering the Orchard pool and prevents more funds from leaving than entered. Ironwood also incorporates ZIP 2005, a quantum-resilience feature designed to permit recovery of funds if quantum computers break current cryptographic assumptions, though the protection applies only to coins migrated into the new pool and not to legacy holdings. Node operators must install the Zcash Foundation's Zebra 6.0.0 release before the activation block.

The lock-in follows the May disclosure of a counterfeiting bug in Orchard discovered by Shielded Labs researcher Taylor Hornby in the proof system used to verify Orchard payments. The flaw could have allowed undetected creation of fake ZEC, but because Orchard hides transaction amounts, the network could not prove that no counterfeit coins existed. The Zcash Open Development Lab patched the bug within days, and ZEC fell as much as 30%, dropping to $385.80 at the low. Ironwood's turnstile is intended to make any counterfeited funds unspendable.

Zcash founder Zooko Wilcox warned in published user guidance that a more practical risk accompanies the mandatory migration: exiting the old pool is publicly visible on-chain as an amount, and while identities remain hidden, the server a wallet connects to can record the user's IP address. "So for every user, the number one most important issue is having network-level privacy (i.e. Tor or Nym) before migrating," Wilcox wrote. He also flagged ongoing scam activity, with impersonators already posing as Ironwood migration support. The Nym project publicly advised users to enable Tor or Nym before moving funds, citing the same network-level exposure.

The Ironwood upgrade is the network's largest coordinated pool migration to date and effectively forces holders to move into a successor pool rather than continue using the deprecated one. Developers have stated that any counterfeit coins, if they exist, would remain permanently stuck in Orchard once the turnstile is active.