Zcash activated Ironwood upgrade sealing vulnerable Orchard pool and introducing new privacy pool with formal verification and withdrawal caps.
Tech & Launches ·
Zcash activated its Ironwood network upgrade on July 28 at block 3,428,143, restricting the original Orchard shielded pool and routing its 3.66 million ZEC through a new privacy pool built with formal verification and independent security audits. The upgrade introduces a "turnstile" mechanism that enforces a hard cap on withdrawals, preventing the pool from paying out more than it has received. This architecture allows the supply integrity of funds exiting Orchard to be verified independently without exposing the private transaction history within the sealed pool.
The activation addresses a critical soundness vulnerability discovered in Orchard in May by Shielded Labs researcher Taylor Hornby. According to the project, there is no evidence the flaw was exploited, that user funds were compromised, or that the total ZEC supply was affected. However, Zcash's privacy design creates a unique verification challenge: hidden transaction values inside a shielded pool cannot be inspected to detect counterfeit issuance, making boundary controls essential.
Ironwood strengthens the cryptographic foundation itself through formal mathematical verification of its protocol design, combined with independent security review. Users can migrate their Orchard holdings to Ironwood directly through compatible wallets, with no new address generation required. The upgrade preserves Zcash's privacy guarantees while substantially hardening the protocol against future soundness issues.