Two-Tier Architecture
Proving and consensus run on separate tiers. Validators never touch raw PQC signatures.
Architecture Overview
Validators verify proofs, not signatures. Separating proof generation (Sentries) from consensus (Validators) is how QBit gets post-quantum security without the bandwidth overhead that makes naive PQC gossip infeasible.
Tier 1: Validators — The Governors
Validators maintain the DAG structure, verify ZK proofs at polylogarithmic cost, perform data-availability sampling, and execute state transitions. They never touch raw PQC signatures, so hardware requirements stay modest.
Tier 2: Sentries — The Provers
Sentries are permissionless proof miners. They pull transactions from the mempool, verify ML-DSA-65 signatures, assemble batches, and generate STARK proofs that compress a full batch into one succinct proof. Anyone with the hardware can run one.
Transaction Lifecycle
Creation
Submission
Aggregation
Proving
Submission to L1
Finalization
User signs transaction with ML-DSA-65
Transaction enters Sentry mempool
Batch of 1,000 transactions assembled
STARK proof π + state diff Δ generated (3.5–5s)
(π, Δ) enters Validator DAG
Proof verified, DA sampled, state diff applied (~3s)
Creation
User signs transaction with ML-DSA-65
Submission
Transaction enters Sentry mempool
Aggregation
Batch of 1,000 transactions assembled
Proving
STARK proof π + state diff Δ generated (3.5–5s)
Submission to L1
(π, Δ) enters Validator DAG
Finalization
Proof verified, DA sampled, state diff applied (~3s)
Data Availability
FRI-based polynomial commitments provide data availability guarantees with no trusted setup and full post-quantum security. Committed data is encoded as evaluations of a low-degree polynomial over the Goldilocks field.
Pre-commitment ensures data is distributed and attested by a quorum of validators before the corresponding proof is accepted into the DAG. This prevents data withholding attacks.
DA sampling uses 30 random queries per block. Each validator independently samples chunks, and a block is only finalized once sufficient attestations confirm availability.
Partition resiliencerequires greater than 2/3 attestation for finalization. With FRI's blowup factor 8, the original data can be reconstructed from any 1/8 of the encoded chunks.
QChains: Sovereign Application Chains
QChains are sovereign application-specific blockchains on top of QBit. They get post-quantum security and shared finality from the main chain. Each QChain runs its own deterministic WASM runtime (verified by SHA3-256 hash) and settles to the QBit DAG. Registration is permissionless. No governance vote needed.
Bridgeless cross-chain messaging QChains communicate via Merkle proof verification against the shared DAG. No bridges, no relayers, no challenge periods. A message from QChain A is finalized on QChain B once the proof is verified on the DAG.
Status lifecycle QChains have three states: Active (fully operational), Degraded (below minimum Sentry count), and Retiring (90-day deregistration notice before shutdown).