RSK (Rootstock) — Smart Contracts Secured by Bitcoin Mining

RSK (Rootstock) Explained

RSK (now often called "Rootstock") is a smart contract platform secured by Bitcoin's hashrate through merge-mining. It's the Ethereum Virtual Machine running on Bitcoin's security. If that sounds wild, that's because it is.

How RSK Works

Merge Mining

RSK uses merge mining — Bitcoin miners simultaneously mine both Bitcoin and RSK blocks with zero additional energy cost. The miner includes an RSK block reference in their Bitcoin coinbase transaction. If the Bitcoin block is valid, the RSK block is too.

Over 60% of Bitcoin's hashrate participates in RSK merge mining. This makes RSK the most hashrate-secured smart contract platform in existence.

The 2-Way Peg (Powpeg)

RSK uses a Powpeg (Proof-of-Work peg) to bridge Bitcoin:

1. Lock BTC on the Bitcoin blockchain
2. Receive RBTC (RSK Bitcoin) on the RSK chain
3. Use RBTC to interact with smart contracts
4. Peg back out to receive BTC on the main chain

The peg is secured by hardware security modules (HSMs) held by the Powpeg federation. It's more trust-minimized than Liquid's peg but still involves federation trust.

EVM Compatibility

RSK runs the RVM (RSK Virtual Machine), which is EVM-compatible. This means Solidity smart contracts from Ethereum can be deployed on RSK with minimal modifications. DeFi protocols, NFT platforms, and other dApps can run on RSK secured by Bitcoin.

The Ecosystem

• Sovryn: DeFi platform for Bitcoin lending, borrowing, and trading
• Money on Chain: Bitcoin-collateralized stablecoin (DOC)
• RIF (RSK Infrastructure Framework): Services layer including naming, storage, and payments
• Tropykus: Latin America-focused lending and savings

RSK vs Other Bitcoin L2s

Feature	RSK	Liquid	Stacks
Consensus	Merge-mined	Federated	Proof of Transfer
Smart contracts	Yes (EVM)	Limited (Elements)	Yes (Clarity)
Security source	Bitcoin hashrate	Federation	Bitcoin PoW (indirect)
Block time	30 seconds	60 seconds	~10 minutes

My Assessment

RSK is technically impressive — merge-mining is elegant. But adoption has been limited compared to Ethereum L2s. The ecosystem is small, and the DeFi TVL is modest. I think RSK's value proposition becomes stronger if Bitcoiners decide they want DeFi without trusting Ethereum's security model. The merge-mining security guarantee is genuinely unique.

RSK answers the question: what if you could have Ethereum's programmability with Bitcoin's security? The technology works. The question is whether enough people care.

More on Bitcoin layer 2 options at our learning center.