# Proof-of-Work vs Proof-of-Stake on QRL

> QRL Legacy is mined (Proof-of-Work); QRL 2.0 is staked (Proof-of-Stake). Here's what that difference actually means.

QRL runs as two chains, and one of the biggest differences between them is **how they agree on the next block**. [QRL Legacy](/learn/glossary#qrl-legacy) is a [Proof-of-Work](/learn/glossary#proof-of-work) chain — it is *mined*. [QRL 2.0](/learn/glossary#qrl2) is a [Proof-of-Stake](/learn/glossary#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](/learn/glossary#coinbase) transaction of newly minted coins).

QRL Legacy uses a Proof-of-Work algorithm called **[QRandomX](/learn/glossary#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](/learn/glossary#validator)**. 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](/learn/glossary#slashing), which destroys part of the stake.

QRL 2.0's Proof-of-Stake runs on a **[beacon chain](/learn/glossary#beacon-chain)** operated by the `qrysm` consensus client, paired with the `gqrl` execution client. Time is divided into fixed **[slots](/learn/glossary#slot)** of 60 seconds, grouped into **[epochs](/learn/glossary#epoch)** of 128 slots (about 2.1 hours), which the protocol uses to assign duties and finalise blocks. Rewards reach validators as protocol **[withdrawals](/learn/glossary#withdrawal)** rather than mined block rewards.

Security comes from stake-at-risk: attacking the chain means risking the validators' own deposits.

## Side by side

![Block production compared: on QRL Legacy, miners spend electricity to solve a QRandomX puzzle and produce a new block secured by hash power; on QRL 2.0, validators stake coins, the beacon chain selects a proposer, and a new block is produced about every 60 seconds, secured by the staked coins.](diagram:pow-vs-pos "How each chain adds a block: Proof-of-Work miners solve a QRandomX puzzle (security = hash power); Proof-of-Stake validators are selected by the beacon chain (security = staked coins).")

| | 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](/learn/qrl-legacy-vs-qrl2).

## Where to go next

- [Validators and staking](/learn/validators-and-staking) — how staking works in practice on QRL 2.0.
- [Slots, epochs and the beacon chain](/learn/slots-epochs-beacon-chain) — the consensus clock.
- [The QRL → QRL 2.0 migration](/learn/the-qrl-migration) — how the two chains connect.