QRL runs as two chains, and one of the biggest differences between them is how they agree on the next block. QRL Legacy is a Proof-of-Work chain — it is mined. QRL 2.0 is a Proof-of-Stake chain — it is staked. This guide explains what that means without the jargon.
Why a blockchain needs "consensus"
A blockchain is a shared ledger with no central operator. Thousands of independent computers need to agree on one history: which transactions happened, and in what order. The rule they use to agree — and to decide who gets to add the next block — is the consensus mechanism. Proof-of-Work and Proof-of-Stake are two different answers to the same question: how do we make it expensive to cheat?
QRL Legacy: Proof-of-Work (mining)
In Proof-of-Work, computers called miners race to solve a hard mathematical puzzle. The puzzle is deliberately costly: the only way to solve it is to try enormous numbers of guesses, which burns electricity. The first to solve it gets to add the next block and collect the block reward (a coinbase transaction of newly minted coins).
QRL Legacy uses a Proof-of-Work algorithm called QRandomX — a QRL variant of RandomX, tuned to favour ordinary CPUs over specialised mining hardware (ASICs), which keeps mining more accessible.
Security comes from cost: to rewrite history, an attacker would need to out-compute the entire honest network, which is prohibitively expensive in hardware and energy.
QRL 2.0: Proof-of-Stake (staking)
QRL 2.0 replaces miners with validators. Instead of spending electricity, a validator locks up — stakes — an amount of QRL as a security deposit. The protocol then selects validators to propose and confirm ("attest") blocks. Honest work earns rewards; provable cheating is punished by slashing, which destroys part of the stake.
QRL 2.0's Proof-of-Stake runs on a beacon chain operated by the qrysm consensus client, paired with the gqrl execution client. Time is divided into fixed slots of 60 seconds, grouped into epochs of 128 slots (about 2.1 hours), which the protocol uses to assign duties and finalise blocks. Rewards reach validators as protocol withdrawals rather than mined block rewards.
Security comes from stake-at-risk: attacking the chain means risking the validators' own deposits.
Side by side
| QRL Legacy (PoW) | QRL 2.0 (PoS) | |
|---|---|---|
| Who adds blocks | Miners | Validators |
| Cost of honesty | Electricity + hardware | Staked QRL |
| Algorithm / layer | QRandomX | Beacon chain (qrysm) |
| Reward | Mined block reward | Staking rewards (withdrawals) |
| Penalty for cheating | Wasted work | Slashing |
| Energy use | High | Low |
Why QRL is moving from one to the other
QRL 2.0 is the successor chain. The shift from mining to staking mirrors the broader industry move (most visibly Ethereum's) toward lower energy use and a stake-based security model — while keeping QRL's defining feature, quantum-resistant signatures, on both chains. QRL Legacy is not switched off in the process: it becomes a permanent, read-only archive. The relationship between the two chains is covered in QRL Legacy vs QRL 2.0.
Where to go next
- Validators and staking — how staking works in practice on QRL 2.0.
- Slots, epochs and the beacon chain — the consensus clock.
- The QRL → QRL 2.0 migration — how the two chains connect.