Zcash Sets July 28 For Ironwood Upgrade

Zcash has confirmed July 28 as the activation date for its Ironwood network upgrade, one week later than the original target, according to core developer Sean Bowe.

Bowe announced on Thursday that "Zcash's Ironwood mainnet activation height has been set and tagged," with all major ecosystem organisations committed to activation of NU6.3 at block height 3428143, approximately July 28 at 8 a.m. EST.

What Triggered the Upgrade

Ironwood is the solution to an "infinity" bug discovered in May on Zcash's main private transaction pool, Orchard. The vulnerability, present since Orchard's activation in May 2022, was discovered on May 29 by security engineer Taylor Hornby and patched in an emergency fix by June 1.

Shielded Labs said the flaw could theoretically have allowed an attacker to create unlimited counterfeit $ZEC, although it also said it had found no evidence that the vulnerability had been exploited. Developers first disabled Orchard transactions through a temporary network update before activating the NU6.2 hard fork on June 3 to fix the underlying issue and restore the pool.

Following public disclosure of the Orchard vulnerability on June 3, ZEC fell about 50% from $602.68 to $299.25. The token has since recovered part of those losses.

How Ironwood Works

Announced in June, Ironwood closes the current Orchard pool, prevents new activity in it and sets up a new private pool. Funds leaving Orchard must pass through an accounting checkpoint before entering Ironwood, which could produce evidence about whether any counterfeit Zcash tokens were produced through the Orchard bug.

According to Shielded Labs, coins leaving Orchard must pass through this checkpoint before entering Ironwood, creating a process that could reveal evidence if any counterfeit ZEC had been created through the earlier bug. The organisation said users migrating funds effectively force any hypothetical counterfeiter to either move fake coins and risk exposing them, or leave those coins behind without a future way to transfer them.

Earlier concerns raised by Shielded Labs that exchanges, mining pools, and wallet providers might not have enough time to prepare, partly because many were also replacing Zcash's long-running zcashd software with the new Z3 stack, including Zebra, Zaino, and Zallet, were ultimately set aside. The upgrade proceeds about a week later than a previously targeted July 21 activation date.

CoinTelegraph: Zcash Sets Ironwood Network Upgrade for July 28 | Crypto.news: Zcash Confirms July 28 Ironwood Activation After Orchard Bug | CoinDesk: Zcash Plummets 38% as Shielded Labs Reveals Major Bug