Around 4,000 BTC left a bridge on Sunday. No key was compromised. The signers signed a withdrawal that was correct by every rule they could check, because the sidechain software had created coins indistinguishable from everyone else's. Twenty-three minutes after those coins reached the peg-out service, the payment was on Bitcoin.
Everything worked as designed. Three properties of that design decided the outcome, and none of them is about honesty.
@pogun_io @omerh_
Between burn and payout there is a proof and a time window.
The operator fronts the withdrawal from their own funds, so the user is not waiting. To be reimbursed, the operator posts a claim carrying a Groth16 proof that the burn of that specific NFT happened and that the fronted payment landed on Bitcoin.
A false proof cannot be forged. A false claim can still be posted, but one honest verifier is enough to stop it.
None of this makes software bug-free.
A ledger bug is a ledger bug, and the answer is audits, formal verification, and engineering practice held to safety standards.
What the design changes is what a bug can reach: one UTxO, through one proof, after a delay, out of an operator's pocket first.
Isolation is not a new idea. Every safety standard for systems that can kill people starts with it.
A good friend of mine did this, currently preprod testnet only. Try it.
explorer.monotonic.tech/
The Mithril zero-knowledge light client verifies Cardano's own state inside a Cardano contract. It carries two costs: proving the certificate chain off-chain, and verifying that proof on-chain. Both are coming down.
The van Rossem hard fork adds CIP-133: that same multi-scalar multiplication as a native Plutus builtin. Moving it out of hand-written script and into the protocol will cut the dominant on-chain cost significantly.
A smart contract on #Cardano can now verify a proof of almost anything.
A proof of Cardano's Mithril certificate chain, verified on Cardano itself. Preprod, live, open.
A Plutus contract checked a zero-knowledge proof that the certificate chain had reached a new checkpoint, and advanced its on-chain record of that chain. A chain of 103 certificates, proven by a 388-byte SNARK, verified in a single transaction.
Transaction: preprod.cexplorer.io/tx/cd01…
Full anatomy: gist.github.com/Sbcdn/ef020f…
The work is open and not yet audited. Review it, break it, help harden it.
Built on RISC Zero (@RiscZero), and the light client uses on the ongoing work of our great Mithril team (@TeragoneFactory).
github.com/blocksmithy/risc0…
github.com/blocksmithy/risc0…
github.com/blocksmithy/mithr…
#Cardano
