asset · quantum risk
Is Across Protocol (ACX) Quantum Proof?
Verdict
Across is not quantum-proof. Bridging intents and pools use classical EVM signatures and relayer/oracle dependencies.
Overview
Across is an intents-based bridge popular on OP-Stack and Ethereum. Quantum risk is user EOAs, LP keys, relayers, and oracle integration.
Fast fills do not change signature hardness.
Exposure summary: Intent/bridge relayers and LP pools; user EOAs on origin/destination. Signature surfaces: ECDSA-secp256k1; Relayer / UMA oracle related keys as integrated. Inventory holders, operators, and any bridge/issuer paths before treating ACX as quantum-ready. Educational only.
Cryptographic profile
What breaks
- Classical signatures authorizing ACX value under Shor-class adversaries once public keys are known
- Custodial hot wallets and exchange operational keys
- Bridges, issuers, or operator sets outside ordinary user wallets
- Protocol admin, oracle, or guardian keys
Mitigations
- Inventory every key that can move ACX (self-custody, exchange, multisig, protocol roles)
- Name the host chain and bridge path for every balance
- Document operator/admin sets for L2s and apps
- Track ecosystem PQC research; branding is not deployment
- Use /assessment and claims methodology pages for program framing
FAQ
Intents = PQC?
Intent UX is application design; crypto remains classical host-chain signatures.
Related?
Bridges hub, Optimism, Ethereum.
Key concepts (technical dictionary)
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