QPoW Consensus & Mining

Quantus uses a custom Proof-of-Work consensus mechanism called QPoW (Quantum Proof-of-Work). It replaces SHA-256 with Poseidon2 hashing, so the mining algorithm and ZK proof system share the same hash function.

Why Proof of Work?

Quantus is a store of value, not a smart contract platform. PoW provides:

• Fair distribution: Anyone can mine, no minimum stake required
• Censorship resistance: No validator set that can be coerced
• No plutocracy: Wealth doesn't compound into more consensus power
• Proven security model: 15+ years of battle-tested economics from Bitcoin

How QPoW Works

The mining algorithm uses double Poseidon2 hashing instead of SHA-256:

nonce_hash = Poseidon2(Poseidon2(block_hash || nonce))
valid = nonce_hash < (U512::MAX / difficulty)

A miner finds a valid block by searching for a nonce where the double Poseidon2 hash is below the difficulty target.

Why Poseidon2?

Poseidon2 was chosen for ZK circuit efficiency, not for quantum resistance (SHA-256 is already quantum-resistant enough). The benefit is that mining work can be efficiently verified inside ZK proofs, which enables future features like provable mining statistics and ZK-verified mining pools.

Mining Flow

Chain Parameters

Parameter	Value	Description
Block Time	12 seconds target	TARGET_BLOCK_TIME_MS
Max Reorg Depth	180 blocks	MaxReorgDepth
Difficulty Adjustment	+/-10% per block	DifficultyAdjustPercentClamp
EMA Smoothing	alpha = 0.1	EmaAlpha = 100/1000
Finalization	179 blocks behind best	MaxReorgDepth - 1
Native Token	QU (12 decimals)	Max supply 21,000,000
SS58 Prefix	189	Addresses start with qz...

Difficulty Adjustment

Difficulty adjusts on every finalized block using an exponential moving average (EMA):

1. Compute actual block time for the finalized block
2. Apply EMA smoothing: ema = actual_time * alpha + prev_ema * (1 - alpha)
3. Compare EMA to target block time
4. Adjust difficulty up or down, clamped to +/-10% per adjustment

This produces smoother difficulty curves than Bitcoin's 2016-block epoch adjustments, responding faster to hashrate changes while avoiding oscillation.

Chain Selection: Heaviest Chain

Instead of "longest chain" (most blocks), Quantus uses heaviest chain (most cumulative work):

• Each block adds its difficulty to the chain's TotalWork
• Fork choice selects the chain with highest TotalWork
• This correctly weights high-difficulty blocks over many easy blocks

Finalization occurs automatically at MaxReorgDepth - 1 blocks behind the best block (179 blocks), meaning blocks older than ~36 minutes are considered final.

Mining Modes

Local Mining (Built-in)

The node binary includes a built-in miner for testing and small-scale mining:

./quantus-node \
    --validator \
    --chain dirac \
    --rewards-preimage <YOUR_PREIMAGE>

Processes 50,000 nonces per batch.

External Mining

For higher performance, a separate miner process offloads the PoW computation:

# Start the external miner
./quantus-miner

# Start the node pointing to the external miner
./quantus-node \
    --validator \
    --chain dirac \
    --external-miner-url http://127.0.0.1:9833 \
    --rewards-preimage <YOUR_PREIMAGE>

The external miner communicates via HTTP API on port 9833, receiving mining jobs and submitting solutions.

Source: quantus-miner

GUI Miner

A desktop application built with Tauri wraps the miner CLI for non-technical users.

Source: miner-tauri-gui

Mining Rewards

All mining rewards are sent to wormhole addresses derived from the miner's preimage. This is not optional. It is built into the protocol.

Wormhole Address Derivation for Miners

1. Generate a wormhole key pair: ./quantus-node key quantus --scheme wormhole
2. The inner_hash (preimage) is used as the --rewards-preimage parameter
3. The node derives the wormhole address on startup
4. All block rewards and transaction fees are sent to this address

This means mining rewards are automatically privacy-preserving. The miner's identity is not linked to their reward address onchain.

Emission Schedule

Quantus uses smooth exponential decay instead of Bitcoin's abrupt halvings:

Block Reward = (MaxSupply - CurrentSupply) / EmissionDivisor

• No halving cliffs that disrupt mining economics
• ~99% of supply emitted within ~40 years
• Miners receive 50% of total supply over time
• Company receives 15% via dev tax on block rewards (~5 years to fully vest)

Fee Structure

Transaction Type	Fee Model
Standard transfer	Miner tip (priority fee)
Wormhole / High-Security	Volume fee split between miner and burn

Key Source Code

Component	Repository	Path
QPoW math (nonce hash, validation)	chain	qpow-math/src/lib.rs
Consensus engine	chain	client/consensus/qpow/
QPoW pallet (difficulty, rewards)	chain	pallets/qpow/
Mining rewards pallet	chain	pallets/mining-rewards/
External miner	quantus-miner	Root
Miner GUI	miner-tauri-gui	Root
Poseidon2 hash function	qp-poseidon	Root