Bitcoin Rollups Without Validity Proofs

Bitcoin's scripting language is intentionally limited. It can't natively verify complex state transitions or SNARK proofs, making Ethereum-style ZK-rollups impossible. The Solution: Build a separate execution environment that uses Bitcoin solely for data availability and dispute resolution, not proof verification.

• Key Insight: Treat Bitcoin as a supreme court, not a calculator.
• Trade-off: Achieves high throughput by moving computation off-chain, but introduces new trust models.

An SDK for launching rollups that post transaction data to Bitcoin (as inscriptions or in taproot leaves). It forgoes validity proofs for a sovereign model where the rollup's own node operators determine canonical state.

• Mechanism: Uses Bitcoin as a robust, immutable data layer.
• Security Model: Inherits Bitcoin's liveness and data availability; security falls to the rollup's own validator set (similar to Cosmos).

If you can't prove validity, you can prove fraud. Projects like Citrea and Chainway implement optimistic rollups where a single honest watcher can challenge invalid state transitions using Bitcoin's limited script.

• Core Tech: A challenge game, enforced via Bitcoin timelocks and multisig, slashes bonded operators.
• Comparison: Similar security model to early Optimism, but the dispute layer is Bitcoin, not Ethereum.

A fully EVM-compatible sidechain secured by a Proof-of-Stake validator set that stakes Bitcoin (via a two-way peg). It's a rollup in spirit (separate execution) but a sidechain in architecture.

• Differentiator: No data posted to Bitcoin L1; uses a decentralized multisig for peg security.
• Goal: Maximize developer onboarding via EVM tooling while using Bitcoin as the base asset.

Without validity proofs, these systems exist on a spectrum between trust-minimization and performance. Sovereign rollups (Rollkit) offer max flexibility but less baked-in security. Optimistic rollups (Citrea) add a fraud-proof layer for stronger guarantees.

• Reality Check: These are not "trustless" like ZK-rollups; they introduce new committees, multisigs, or honest-minority assumptions.

This is the foundational battle for Bitcoin's future: Lightning Network (payment channels) vs. Drivechains (federated sidechains) vs. Client-Side Validation (like RGB) vs. Rollups. Non-proof rollups represent a pragmatic middle ground, offering scalable smart contracts without requiring changes to Bitcoin consensus.

• Endgame: To capture DeFi and stablecoin activity without waiting for Bitcoin protocol upgrades.

Bitcoin L1 lacks a native, cheap validity proof system (like Ethereum's precompiles for zk-SNARKs). Forcing it creates massive client-side overhead and centralization risks.\n- No Native VM: Can't verify complex state transitions on-chain.\n- Client Burden: Users must validate entire chain history, defeating scalability.\n- Security Reliance: Falls back to honest-majority assumptions of a smaller validator set.

Projects like Rollkit and Citrea use Bitcoin purely as a data availability and finality layer. Execution and settlement are sovereign.\n- Data Commitments: State roots posted via OP_RETURN or taproot.\n- Fraud Proofs Optional: Can use multi-sig committees for faster, simpler challenges.\n- L1 Leverage: Inherits Bitcoin's $1T+ security for data ordering, not execution correctness.

You exchange cryptographic certainty for operational simplicity and faster time-to-market, similar to early Optimistic Rollups.\n- Trusted Validators: Security depends on a 2-of-3 or m-of-n multisig bridge.\n- Capital Efficiency: No need to lock capital in a smart contract for proofs.\n- Ecosystem Risk: Fragmentation across multiple sovereign chains without shared security.

This is the Bitcoin-native approach, championed by systems like RGB and Taro. Users validate only the history relevant to their UTXOs.\n- Single-Use-Seals: Bitcoin transactions act as commitment anchors.\n- Proof of Publication: Validity is enforced by the threat of publishing fraud proofs to the Bitcoin chain.\n- Massive Parallelism: Each asset ledger operates independently, avoiding global state bottlenecks.

Moving value between Bitcoin and a non-validity rollup requires a trusted custodian or federated peg, creating a central point of failure.\n- Federated Multi-sig: Models like Liquid Network's 15-of-15 functionaries.\n- Watchtower Networks: Required to monitor for theft, adding operational overhead.\n- Capital Lock-up: Bridges require substantial BTC reserves, reducing capital efficiency.

Deploying a functional scaling solution today beats waiting years for mature validity proof systems on Bitcoin. Capture developer mindshare and TVL.\n- EVM Compatibility: Can port Uniswap, Aave forks immediately using Rollkit.\n- Regulatory Clarity: Sovereign chains may face simpler regulatory treatment than L1.\n- Path to Validity: This stack can later integrate zk-validiums once Bitcoin's proof ecosystem matures.