But evidence points away from exploitation, a CoinDesk Research report found in July. If someone had minted fake ZEC, the obvious next step would be to move it out and sell it, which would show up as funds leaving the pool. However, Orchard’s balance grew steadily over the four years the fault was open, including through last year’s price increase, when paying out would have been most profitable.
Developers fixed the bug within days, but the patch failed to account for the four years it was open. A zero-knowledge proof reveals nothing beyond the facts it confirmed, so the chain has no record of whether any Orchard transaction actually moved, and no one can prove that fake coins were never created.
The turnstile is an answer to that. Money crossing into or out of a shielded pool is public, even when the transactions inside are not, so the network already knows how much ZEC went into Orchard and won’t release more than that. Any fake coins sitting inside are stuck there.
As of press time, 1,500 ZEC have already moved into the new pool, according to a tracker.
Ironwood was also launched with two protections Orchard never had. The record each coin leaves on chain is built to remain recoverable if quantum computers eventually break the cryptography that now secures it, a property specified under ZIP 2005 and in place from the first block.
