Zcash Activates Ironwood Upgrade to Prevent Counterfeit Coins
Zcash has activated its Ironwood upgrade, designed to prevent counterfeit coins from entering circulation after a critical vulnerability was discovered in May. The vulnerability, which could have allowed an attacker to create fake ZEC, sparked a market rout and raised questions about the cryptocurrency's supply.
The Ironwood upgrade replaces the Orchard shielded pool with a new one, begins migrating users into it, and introduces new accounting rules for Zcash's circulating supply while preserving the network's privacy guarantees. The old pool holds roughly 3.7 million ZEC worth around $1.7 billion.
Developers issued an emergency patch in June after security researcher Taylor Hornby discovered a four-year-old flaw in Orchard, but because shielded transactions intentionally hide their details, there was no way to prove whether the vulnerability had ever been exploited.
The uncertainty sparked a sharp selloff, with Zcash falling 38% as investors questioned whether the cryptocurrency's supply could be trusted. However, news of Ironwood led to a rebound in Zcash, recovering roughly $2.5 billion in market value in early June as investors welcomed the proposed fix.
Critics argue that the migration creates a temporary privacy risk, and developers have advised users not to rush the migration and recommend using privacy tools such as Tor or NymVPN while moving funds. The upgrade also introduces quantum-resistant transaction records and a formally verified proof circuit intended to reduce the risk of similar vulnerabilities in the future.