The Zcash Foundation developers have released Zebra 6.0.0 and recommended all node operators upgrade to the fork. The update includes a new shielded pool and transaction format v6.
Its release is related to a vulnerability discovered in the old Orchard pool, which could have allowed an attacker to covertly create counterfeit $ZEC.
The developers addressed the vulnerability with emergency patches in June. At the same time, they did not find any evidence of the vulnerability being exploited, but Zcash's privacy architecture does not allow them to state this with complete certainty.
According to the Zebra 6.0.0 release notes, Ironwood uses the Orchard action structure and the Halo2 proof system. It also adds a separate note commitment tree, a set of nullifiers, a network value pool, and network history data. Once activated, these records allow nodes to track the new pool independently of Orchard.
Zebra also updates several node commands so operators can check the state of the pool and the commitment tree. On GitHub, this update is marked as critical for operators because the old software will not follow the correct network after the activation height is reached.
The primary supply protection mechanism of Ironwood is a kind of "turnstile" between Orchard and the new pool. After activation, Orchard will stop accepting new outputs and internal transfers. Funds can be withdrawn, but a value accounting rule prevents withdrawing more $ZEC from Orchard than was legitimately added to it.
The Ironwood design description notes that this mechanism provides users with public oversight over the circulating supply without revealing private balances or transaction details. After withdrawals, any excess capital will remain locked inside Orchard.
As Happy Coin News previously reported, Zcash scheduled the hard fork for July 28 after developers confirmed the fixed bug raised doubts about supply inflation.
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