Zcash's Ironwood Shield Pool Goes Live Amid Counterfeit Mitigation Efforts

Zcash's NU6.3 network upgrade was implemented on July 28, bringing a new shield pool called Ironwood into operation.

The upgrade stopped new deposits to Orchard and outbound transactions from it, but existing assets are not frozen and can be moved to either Ironwood or a transparent address using compatible wallets.

The move comes after a critical vulnerability was discovered in Orchard's verification circuit, which could have allowed unlimited and undetectable counterfeit ZEC to be generated. The issue was reportedly present for around four years before being found by researcher Taylor Hornby in May 2023.

A subsequent network upgrade (NU6.2) introduced a modified verification circuit, but the new shield pool Ironwood takes further steps to mitigate the risk of counterfeiting by introducing a 'turnstile' mechanism that prevents excessive withdrawals and helps maintain supply chain transparency.