Citrea, Bitcoin’s First ZK Rollup, Emerges from Stealth

[PRESS RELEASE – Grand Cayman, Cayman Islands, February 6th, 2024]

Citrea is the first rollup that enhances the capabilities of Bitcoin blockspace with zero knowledge technology, enabling developers to build everything on Bitcoin

Citrea, Bitcoin’s first ZK rollup, has come out of stealth today to enable developers to build everything on Bitcoin. Citrea is the first-ever and only execution layer that settles on Bitcoin. Every transaction occurring on Citrea is fully secured by zero-knowledge proofs and verified by Bitcoin through BitVM. Citrea represents a major milestone for Bitcoin, marking a first as the most secure way to scale Bitcoin, entirely aligning with its incentives. The developer contact form opens today for those who want to build on Citrea and its developer docs are finally unveiled to the public.

Bitcoin has faced the critical challenge of how to handle more transactions and support more diverse applications without compromising Bitcoin’s founding principles – security, consensus rules, and censorship resistance. While scalability proposals have been presented in the past, they have consistently failed to address a critical point in Bitcoin scalability – the active and effective utilization of the Bitcoin blockchain itself.

Zero-knowledge proofs are the only way to securely scale Bitcoin and achieve easy verification by the Bitcoin blockchain. ZK rollups, specifically, are the only rollup construction that can fit into Bitcoin’s block size limit effectively.

Citrea is the first to bring ZK Rollups to Bitcoin, expanding what developers can build on Bitcoin and introducing Bitcoin’s next phase: foundation for the world’s financial infrastructure. Citrea enhances Bitcoin’s blockspace capabilities. Its execution environment is trustless to Bitcoin and available to all participants of the Bitcoin network. Citrea validity proofs are inscribed in Bitcoin and optimistically verified on Bitcoin via BitVM, for the first time in Bitcoin history. By doing so, Citrea creates consistent fee revenue for miners through data availability, trustlessly scales BTC beyond Bitcoin with validity proofs, and allows developers to build anything on its EVM equivalent execution shard.

“Citrea aims to make Bitcoin the bedrock for a vast array of on-chain applications and financial activities, where developers can build anything. While previously scaling proposals have been well-intentioned, we can only establish Bitcoin as the global standard for decentralized financial infrastructure if transactions settle on Bitcoin,” said Murat Karademir, Cofounder and COO of Chainway Labs, the company building Citrea.

Citrea brings a modular and flourishing ecosystem anchored on Bitcoin. It creates a future where Bitcoin blockspace is used to settle a variety of financial activities such as trustlessly buying BTC, leveraging BTC, or lending/borrowing BTC. As a result, Citrea presents the long-awaited scaling solution – unlocking Bitcoin’s $800B capital by ensuring its security with the Bitcoin blockchain. With Citrea, developers can build a wide range of applications, including but not limited to DeFi with BTC, private transfers, and swaps with BTC, as well as develop new layers on top of Citrea.

To serve this aim, Citrea’s unique construction gives it key features:

Full Bitcoin Security: Citrea inherits all four security properties of Bitcoin: validity, liveness, re-org resistance and censorship resistance thanks to Citrea’s effective usage of inscriptions, recursive ZK proofs, and BitVM.
Bitcoin Settlement: For the first time in Bitcoin history, a universal L2 is settled on Bitcoin. Citrea light client proofs are natively verified on Bitcoin via BitVM, enabling the first Layer 2 verification in Bitcoin and trust-minimized two-way peg mechanism.
EVM Equivalency: Citrea ships a Type 2 zkEVM, fully equivalent to EVM, built using RISC Zero. Building Citrea with full EVM equivalence enables all the EVM developers to build on Bitcoin, effortlessly. Citrea is not limited to a single VM by design, and can adopt new VMs such as WASM VM in the future thanks to its modular architecture.

“A demand for Bitcoin moved to a sidechain is not a demand for Bitcoin anymore. Truly scaling Bitcoin requires establishing a symbiotic relationship between Bitcoin and the scaling solution,” said Orkun Mahir Kılıç, Cofounder and CEO of Chainway Labs, the company building Citrea. “Therefore, the scaling solution needs to effectively utilize Bitcoin blockspace to scale the demand and increase its expressivity and throughput without changing its protocol. Citrea achieves the most secure and incentive aligned way to scale Bitcoin.”

Today, Citrea as well as its developer docs are finally unveiled to the public. Developers who want to build on Citrea can now start contacting Citrea team through the form on their website. Citrea plans to open source the codebase in the first quarter and launch its testnet later in the second quarter of 2024. Citrea has been developed by Chainway Labs for over a year, who also built Proof of Innocence and OrdinalSafe in the past.

About Citrea

Citrea is the first rollup that enhances the capabilities of Bitcoin blockspace with zero-knowledge technology, making it possible to build everything on Bitcoin. For more information, please visit: https://citrea.xyz

Citrea technical docs: https://docs.citrea.xyz