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Entanglement bridge

Entanglement is the canonical bridge between Quantum and other EVM chains. It uses LayerZero v2 as transport and a DVN-based verification stack, with a hard PQ boundary invariant:

Nothing mints or unlocks on Quantum unless there is post-quantum authorization.

Status: In progress. Deployed chain support, verifier and adapter addresses, and DVN configuration will be published as they go live. The bridge will go through independent audits (bridge + DVN) before mainnet.

Defense-in-depth​

Entanglement enforces the PQ invariant in two ways simultaneously — either alone would be sufficient; together they're conservative:

  1. PQ-DVN required for EVM → Quantum verification. A Decentralized Verifier Network signed by PQ keys must attest to the inbound message before Quantum acts on it.
  2. Quantum-side pending-credit gate. Inbound transfers do not immediately credit the recipient. Instead they materialize as pending credit keyed by guid, and the recipient (or a relayer) must call claim() with a PQ-authenticated transaction to finalize.

The result: a successful inbound bridge requires the message to clear both a PQ-DVN attestation and a PQ-signed claim() on Quantum. Two independent PQ checks gate every mint.

Message lifecycle​

Quantum → EVM (outbound)​

1. User signs PQ-auth tx on Quantum to initiate send.
2. LayerZero v2 transports the message.
3. EVM-side contract verifies the LayerZero stack and mints / releases.

The outbound case is symmetric to any LayerZero v2 bridge once it crosses to the EVM side. The PQ part of the invariant is upstream: the Quantum-side send was PQ-authorized.

EVM → Quantum (inbound boundary)​

1. EVM-side contract burns / locks user assets and emits a LayerZero message.
2. LayerZero transports the message; the PQ-DVN attests.
3. Quantum-side contract records pending credit keyed by `guid`.
4. User (or relayer) finalizes via PQ-authenticated claim().

The pending-credit step is what makes the boundary explicit. Even if a DVN were ever compromised, an attacker would still need a valid PQ signature on Quantum to finalize the claim — and the claim must reference the specific guid that was credited.

Why LayerZero v2​

  • Production-grade transport. Battle-tested, with multiple DVN providers, configurable security stacks, and a maintained code base.
  • DVN composability. We can require a PQ-DVN alongside any other DVNs an integrator wants — defense-in-depth without locking integrators out of multi-DVN configurations.
  • No need to reinvent. Cryptographic and engineering effort is spent on the PQ boundary, not bridge transport.

Scope of the PQ guarantee​

Entanglement preserves a PQ boundary at the Quantum side — nothing mints there without PQ auth. It does not retroactively make every chain on the other side of the bridge PQ-secure. If you're bridging from a chain whose contracts use ECDSA and that chain's classical keys are compromised, the EVM side can still be drained. The Quantum side is the part we control.

This is the same shape as the Threat model for the wallet: the new behavior is guaranteed, but the old cannot be retroactively secured.

  • System overview — where the bridge sits in the wider architecture
  • Threat model — what the PQ boundary protects and what it doesn't
  • Roadmap — current bridge milestones