Boundless unlocks Bitcoin settlement and verification for Ethereum and Base ZK proofs

The Boundless team, developing the zero-knowledge proof network and marketplace launched by RISC Zero, has found a way to use Bitcoin as a settlement and verification layer for computationally expensive zero-knowledge proofs using a “cross-chain verification system.” 

Boundless' new system will initially run from the Ethereum mainnet and Base Layer 2 to Bitcoin, essentially unlocking the largest and most decentralized blockchain as a settlement layer for the popular smart contract chains. 

“Fundamentally, it's not about turning Bitcoin into Ethereum. Instead, it's Ethereum-style execution secured by Bitcoin, not running on Bitcoin,” Boundless CEO Shiv Shankar told The Block. “Bitcoin acts as the ultimate verifier and settlement layer for ZK proofs, and those ZK proofs can express lots of complex computation.”

The move represents the latest advancement for ZK cryptography, a field that, in no small part, found its first large-scale, real-world applications on blockchains. ZK proofs — essentially compact receipts proving that a complex calculation has occurred without leaking transaction details — are used by developers to scale networks and enhance privacy.  

Boundless’ new verification system also taps the Bitcoin Virtual Machine, or BitVM, a somewhat controversial verification framework for validating offchain computation on Bitcoin. Proposed in 2023 and launched in mid-2025, BitVM essentially extends some smart contract capabilities to Bitcoin, without needing to update Bitcoin's core rules or code.

“What BitVM unlocks, and what Boundless is building on, is the ability to anchor real computation to Bitcoin without changing Bitcoin in any way," Shankar said. "That's really the key: there are no protocol changes." 

The launch also taps the Bitcoin-native, ZK-powered rollup, Citrea, according to the announcement. Citrea is among several L2s and other tech paradigms, like OP_CTV, also looking to extend Bitcoin’s functionality. 

“The Bitcoin ecosystem's appetite has shifted from pure store of value toward verifying more without changing consensus,” Shankar said. “There's also a growing need from rollups that want stronger, neutral settlement layers as the L1 wars heat up.”

Although Shankar noted ZKs are “now production-grade,” and faster, cheaper, and more reliable than ever, it has been a technical challenge to unlock them natively on Bitcoin.

“We're here to do the hard things, not the easy things,” Shankar said. “Bitcoin doesn't have native verification primitives, so everything has to be expressed through Bitcoin's scripting model. Bitcoin's verification is more constrained because it's more honest. You're paying for dispute resolution, not continuous execution.”

Boundless, itself powered by RISC Zero’s zkVM proving tool, intends to “expand support for additional chains and ecosystem integrations” beyond Ethereum and Base, laying the “groundwork for Bitcoin to become a shared security layer across the broader blockchain ecosystem.”

To that end, Boundless integrated with the Wormhole bridge in August, aiming to link EVM chains like Avalanche and Base to Solana.