Zcash activates Ironwood upgrade after Orchard security flaw

Zcash has activated its Ironwood network upgrade, introducing a new shielded pool designed to strengthen the security of private transactions and make the integrity of the circulating ZEC supply independently verifiable. The Ironwood NU6.3 upgrade went live Tuesday at block height 3,428,143. The upgrade also introduced a new transaction format supporting the Ironwood shielded pool. Ironwood was developed following the discovery of a critical soundness vulnerability affecting Orchard, Zcash’s previous shielded pool. Security researcher Taylor Hornby discovered the vulnerability on May 29 and privately disclosed it to Zcash developers. The issue affected the zero knowledge proof system used to validate Orchard transactions. There is no evidence that the vulnerability was exploited, that user funds were affected, or that Zcash’s total supply increased. However, the private nature of Orchard transactions means observers cannot examine the amounts inside the pool to definitively determine whether counterfeit ZEC was created. Ironwood addresses the issue by restricting the original Orchard pool. New funds can no longer enter Orchard, while funds leaving the pool must pass through Zcash’s...