Zcash migration reaches 85% completion as Orchard pool winds down to 3% of supply

Zcash’s emergency migration from its compromised Orchard shielded pool to the new Ironwood pool has hit the 85% mark, with just 3% of the total supply still sitting in Orchard.

The Ironwood pool has already accumulated over 3.7 million ZEC, with migration speeds reportedly reaching thousands of ZEC per hour.

From bug discovery to full migration

On May 29, 2026, Zcash developers discovered a soundness vulnerability in the Orchard shielded pool. The flaw could have allowed undetectable counterfeiting of ZEC.

The response came in two phases. First, an emergency patch to stop the bleeding. Then, the more comprehensive NU6.3 upgrade, which introduced Ironwood as a replacement pool with formal verification and quantum-resilient cryptographic elements.

Ironwood went live on July 28, 2026, at block 3,428,143. At that moment, the Orchard pool was officially sealed. Users were expected to move their funds voluntarily through a turnstile mechanism defined by ZIP-318, which preserves privacy during the transfer process.

At the time Ironwood activated, shielded supply in Orchard represented roughly 25% of all circulating ZEC.

Why 85% matters more than it sounds

Mid-August snapshots had the migration at 79.2% complete. The jump to 85% suggests the pace hasn’t meaningfully slowed, even as the remaining pool shrinks.

Wallet providers have been doing the heavy lifting on the user experience side. Cake Wallet and ZODL are among the platforms facilitating the migration, making the process accessible to non-technical holders.

The turnstile mechanism routes transfers through individual wallet actions. Each user initiates their own migration, and the protocol handles the privacy-preserving handoff.

Quantum resistance enters the picture

The Ironwood upgrade introduced quantum-resilient cryptographic components. The formal verification applied to Ironwood’s circuits also addresses the root cause of the original vulnerability. Formal verification uses automated mathematical proofs to ensure that the cryptographic circuits behave exactly as specified.