Zcash activates Ironwood upgrade, restricting legacy Orchard shielded pool ($1.7B) and introducing formally verified shielded pool with turnstile mechanism.
Tech & Launches ·
Zcash activated its Ironwood upgrade, sealing the legacy Orchard shielded pool containing approximately 3.66 million ZEC (valued at roughly $1.7 billion) and opening a new migration pathway with zero initial coins. The move came after researchers discovered a counterfeiting vulnerability in Orchard's proof circuit that had remained undetected since the pool's launch in May 2022, though analysis suggested the flaw was likely never exploited. The upgrade introduces a turnstile mechanism—an accounting boundary that restricts withdrawals from Orchard to the amount verifiably deposited, preventing any counterfeit coins from leaving the legacy pool.
Ironwood incorporates quantum-resilient cryptography for onchain records and formally verified proof circuits that mathematically certify transaction validity. All funds in the legacy pool must be manually migrated by users, with early activity showing 1,500 ZEC moved into the new pool shortly after activation. The mechanism addresses the epistemic problem created by the four-year vulnerability window: because zero-knowledge proofs reveal nothing beyond verification facts, the chain holds no record of whether counterfeit coins were ever created, making the turnstile a permanent safeguard rather than a technical fix.
The speed of voluntary migration from Orchard to the new pool remains uncertain and will determine how quickly Zcash's private supply concentration shifts. No timeline has been specified for when the legacy pool might be fully deprecated, and user adoption patterns of the new formally verified pool are still emerging.