Zcash Completes Ironwood Verification Proof Against Counterfeiting Bugs

Zcash researchers completed formal verification of Ironwood on Tuesday, publishing a machine-checked proof that the network's new shielded pool does not contain undetectable counterfeiting bugs under its stated cryptographic assumptions. Project Tachyon said the proof ensures the shielded pool cannot pay out more value than has publicly entered it. Ironwood was introduced through Zcash's NU6.3 upgrade in response to a vulnerability discovered in its Orchard shielded pool that could theoretically have enabled undetectable ZEC counterfeiting.

Project Tachyon Publishes Lean-Based Proof With 2,700+ Theorems

Project Tachyon said on Tuesday that the proof, written in the Lean programming language, comprises over 2,700 theorems and took three teams of researchers and cryptographers over a month to complete. The work establishes a security property known as balance integrity, designed to ensure the shielded pool cannot pay out more value than has publicly entered it.

Verification Covers Zero-Knowledge Proof System and Circuit Rules

The researchers said the proof covers the components needed for that property, including Ironwood's zero-knowledge proof system, circuit rules and ledger-level accounting. The proof does not cover Ironwood's separate privacy guarantees.

Ironwood Responds to Orchard Shielded Pool Vulnerability

Ironwood was introduced through Zcash's NU6.3 upgrade in response to a vulnerability discovered in its Orchard shielded pool that could theoretically have enabled undetectable ZEC counterfeiting. Zcash developers said they found no evidence that the flaw had been exploited. The new pool was designed to restore confidence in Zcash's supply integrity.

Turnstile Mechanism Blocks Hypothetical Excess Coins From Ironwood

Funds migrating from Orchard must pass through a public accounting checkpoint known as a turnstile, which is designed to prevent any hypothetical excess coins from entering Ironwood. As funds leave Orchard, the process could also provide growing evidence about whether the old pool was exploited.

FAQ

What did Zcash researchers complete on Tuesday? Zcash researchers completed formal verification of Ironwood on Tuesday, publishing a machine-checked proof that the network's new shielded pool does not contain undetectable counterfeiting bugs under its stated cryptographic assumptions.

Why was Ironwood introduced through Zcash's NU6.3 upgrade? Ironwood was introduced through Zcash's NU6.3 upgrade in response to a vulnerability discovered in its Orchard shielded pool that could theoretically have enabled undetectable ZEC counterfeiting. The new pool was designed to restore confidence in Zcash's supply integrity.

What is the turnstile mechanism in Ironwood? The turnstile is a public accounting checkpoint that funds migrating from Orchard must pass through. It is designed to prevent any hypothetical excess coins from entering Ironwood.