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System overview

Execution and consensus on Quantum are intentionally conventional. The novelty is PQ authorization plus PQ scaling, and how that boundary is enforced across bridges, wallets, and marketplaces.

Architecture at a glance​

Layer / DomainWhat runs thereWhat it does
ExecutionEVM-compatible executionFull Ethereum execution ergonomics. Contracts deploy as-is.
ConsensusSimplex (Commonware) + FalconSub-second finality. Falcon for smallest PQ signature size. Threshold DKG under research.
AuthorizationKeyVault + composite tx + native precompiles + 2D noncesPer-account key registry with scoped permissions. Primary signer mandatory (from approved-primary list). Optional cosigner (P256 / ECDSA). Pre-EVM verification at the protocol level. Parallel mempool via NonceManager. Key management via KeyVault precompile.
Entanglement bridgeLayerZero v2 + DVN stack + PQ boundary gateNothing mints without PQ auth. Pending credit → PQ claim().
PQ Wallet LayerPQ smart wallets + native wallet + MithrilDual-mode. PQ smart wallets on EVM chains. Native wallet with MPC, TEE, threshold ML-DSA for institutions.
QCNOn-chain escrow + off-chain executionQuantum job marketplace settled on Quantum (post-mainnet).

Core chain transaction path​

A new transaction flows through these steps. The full 13-step sequence with diagrams lives in Transaction and block lifecycle; this is the executive walkthrough.

  1. Build and sign. The user signs a composite transaction referencing a key_id in their on-chain KeyVault. The primary signature is mandatory; cosigner signature is optional.
  2. Pre-EVM validation. The node intercepts the transaction before EVM execution. It looks up the sender's KeyVault, retrieves the KeyEntry, and verifies the primary signature against the stored public key. If the KeyEntry has Scoped permission, call targets and native value are checked. The 2D nonce is validated. If a fee_payer is present, their composite signature is verified separately.
  3. Lifecycle intent. For key-management operations, the node writes transient state into the KeyVault precompile's storage. The precompile reads this during EVM execution to authorize mutations — direct top-level calls only.
  4. EVM execution. The calls list is executed atomically. If any call fails, all state changes revert. The target contract sees a normal msg.sender and is unaware of the PQ-verification step.
  5. Finalization. The nonce is incremented, state is persisted, and Simplex provides notarization → finalization.

What's new versus standard Ethereum​

For integrators (and especially indexers), the deviations are concrete and short. The full list lives in Indexer architecture.

  • One transaction type. Quantum uses a single custom EIP-2718 type 0x7A. There are no Legacy, EIP-2930, EIP-1559, EIP-4844, or EIP-7702 transactions.
  • Composite signatures. Each transaction carries a primary (mandatory) and optional cosigner — no v / r / s fields.
  • Explicit sender. ML-DSA is non-recoverable, unlike ECDSA ecrecover. The sender is a field, not a function of the signature.
  • Batched calls. A calls: Vec<Call> field replaces the single to / value / input. Atomically executed.
  • 2D nonces. (nonce_key, nonce) for parallel mempool queues.
  • Gas sponsorship. A fee_payer field with its own composite signature, signed over a different domain (0x78 prefix vs 0x7A).
  • Block header has an extra field. timestampMillisPart (0–999) for sub-second consensus ordering; RPC responses include timestampMillis.
  • Native precompiles at fixed addresses for KeyVault (0x1000), NonceManager (0x1001), CryptoSwitchboard (0x1002), ML-DSA-44 verifier (0x1003), Falcon verifier (0x1004), and P256 verifier (0x0100, EIP-7951 canonical).