Zcash users moved about 176,000 ZEC, nearly $81 million, into the freshly activated Ironwood shielded pool just a day after the NU6.3 upgrade went live. This sum represents roughly 5% of the 3.66 million ZEC that were locked in the older Orchard pool prior to the switch.
The Ironwood upgrade, which started at block height 3,428,143 on Tuesday, replaced Orchard as Zcash's main privacy layer. Since then, Orchard no longer accepts new deposits or transfers, only allowing withdrawals through a controlled mechanism designed to prevent the release of any potentially counterfeit coins.
Since the upgrade, Orchard's balance has decreased from around 3.66 million ZEC to about 3.51 million ZEC, but most shielded funds remain in the retired pool. The migration to Ironwood remains voluntary.
Background on the Upgrade
Ironwood was developed after researchers identified a critical vulnerability in Orchard's zero-knowledge circuit, a flaw dating back to Orchard's 2022 launch. This bug could have allowed malicious actors to forge counterfeit ZEC without detection.
Following the discovery, Zcash developers rolled out an emergency patch in June to fix the flaw, but the privacy features of Orchard made it impossible to verify if the vulnerability had ever been exploited. Fortunately, developers found no evidence of counterfeit creation and deemed exploitation unlikely.
Ironwood enhances security by using the patched Orchard circuit along with formal verification methods, independent audits, and extra security reviews. This setup enables node operators to confirm that the total circulating supply of Zcash remains within protocol limits.
This material is for informational purposes only and does not constitute financial advice.
