S15 E18: Orkun Kılıç on Citrea, The First ZK Rollups on Bitcoin

Orkun Kılıç is a Turkish developer who co-founded Chainway Labs – a team of coders that tries to bring ZK rollups to Bitcoin via Citrea. Launched on February 6th 2024 and presented in exclusivity on the Bitcoin Takeover podcast, Citrea is an ambitious initiative which makes use of BitVM’s verification capabilities and inscribes ZK rollups to the Bitcoin blockchain. It’s certainly an unorthodox initiative which comes with an ambitious goal: to take away a significant market share of WBTC (bitcoins custodied by BitGo, issued on the Ethereum blockchain for DeFi applications) and bring it back home to Bitcoin.

What are ZK rollups, you say? Basically, they’re a more efficient way to do transaction batching – but instead of having all the data on the blockchain, the computation happens off-chain (with something like BitVM) while the data concerning the transaction gets compressed into a ZK proof that gets inscribed (and therefore stored) on every node. What does the ZK part stand for? It’s about Zero Knowledge proofs – a type of cryptographic verification which proves or disproves the validity of a question without revealing anything about the contents. It’s really groundbreaking stuff that is slowly but gradually finding its way into Bitcoin.

Bitcoin Takeover podcast season 15 is sponsored by Wasabi Wallet, Cryptosteel, Satochip, and IVPN!

The Significance of Citrea in Bitcoin’s Ecosystem

Citrea is not just another project; it’s the first implementation of zero-knowledge roll-ups on Bitcoin. This means we can now build a plethora of applications on Bitcoin without altering the network’s consensus rules. The promise of Citrea is a world where Bitcoin can handle a multitude of transactions, smart contracts, and decentralized applications with the same level of security but at a fraction of the cost and time.

Orkun Kılıç explains the Technical Underpinnings of Citrea

During our podcast, Orkun Kılıç explained the intricacies of the Citrea project, including the type two zkEVM (zero-knowledge Ethereum Virtual Machine). This allows for full compatibility with the EVM on the Bitcoin blockchain, enabling a seamless transition of applications and smart contracts to Citrea. It’s not about bringing Ethereum to Bitcoin; it’s about unlocking Bitcoin’s full potential.

The Financial Benefits of Citrea

One of the most pressing questions for Bitcoin users is the financial advantage of using Citrea over other solutions like Lightning. Citrea’s roll-ups promise to deliver the same security as Bitcoin but in a more cost-effective and efficient manner. Transactions within the Citrea ecosystem are expected to be ten to twenty times cheaper than on the Bitcoin main chain, making it an attractive option for users and merchants alike.

Orkun Kılıç and the Road Ahead for Citrea

The Citrea project is not just a technological marvel; it’s a vision for a more scalable and user-friendly Bitcoin network. With plans to open source the codebase, including the Bitcoin bridge, and a public testnet slated for April 2024, Citrea is poised to make a significant impact on the Bitcoin community.

Listen to Orkun Kılıç talk about Citrea and Zero Knowledge Rollups on Bitcoin on Apple Podcasts, Spotify, YouTube & X!

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Time stamps for my interview with Orkun Kılıç:

The project called Citrea (00:00:50) Discussion about the Citrea project, its focus on zero knowledge proofs, roll ups, and its significance in Bitcoin’s scalability.

Introduction to Citrea project (00:01:58) Orkun Kılıç introduces the Citrea project, the first implementation of zero knowledge rollups on Bitcoin.

Roll ups and zero knowledge proofs (00:02:24) Explanation of roll ups as on-chain layer tools and the use of zero knowledge technology to validate transactions.

Comparing roll ups to sidechains (00:04:31) Comparison of roll ups and sidechains, highlighting the differences in security assumptions and consensus.

Role of zero knowledge proof scheme (00:06:11) Explanation of the role of zero knowledge proofs in validating transactions and the differences between optimistic rollups and zero knowledge rollups.

Background and motivation for Citrea project (00:08:29) Orkun Kılıç explains the background and motivation for developing the Citrea project and its significance in Bitcoin’s scalability.

Discussion on inscriptions and their impact (00:12:34) The impact of inscriptions on Bitcoin’s innovation and the potential for scaling solutions beyond just embedding data like jpegs.

Importance of non-custodial solutions (00:17:12) Discussion on the importance of non-custodial onboarding and scaling in the context of Bitcoin’s culture and ethos.

Introduction to the Citrea project’s architecture (00:18:20) Introduction to the Citrea project, its architecture, and the use of Type 2 SSC EVM for full compatibility.

Inscribing zero knowledge proofs in Bitcoin (00:23:00) Explanation of inscribing zero knowledge proofs in Bitcoin and ensuring permissionless access for every node in the Bitcoin network.

Size of zero knowledge proofs (00:23:50) Discussion on the size of zero knowledge proofs and the efficiency of data compression in the Citrea project’s architecture.

The scalability benefits of Citrea (00:25:32) Discussion on compressing proofs and transaction fees, enabling tens of times more Bitcoin transactions on Citrea.

The significance of rollups for Bitcoin scalability (00:26:28) Exploration of the impact of rollups on Bitcoin’s scalability and the potential reduction in transaction fees.

Zero knowledge proofs and privacy benefits (00:31:39) The potential for building private applications on Citrea using zero knowledge proofs and the implications for privacy.

Trade-offs and challenges in Citrea’s implementation (00:32:39) Discussion on the trade-offs, challenges, and the need for trust minimization in Citrea’s implementation.

Decentralized sequencer network in Citrea (00:34:53) Explanation of the development of a decentralized sequencer network to enhance security and finality in Citrea.

Scalability and verification in Citrea (00:36:08) Explanation of the scalability benefits and the use of zero knowledge proofs for efficient verification in Citrea.

Universal trust-minimized two-way peg in Citrea (00:39:51) Explanation of Citrea’s claim to have the first universal trust-minimized two-way peg and its significance.

Adoption and comparison with sidechains (00:42:38) Discussion on the adoption of Citrea within the Bitcoin community and a comparison with sidechains.

Fraudulent possibilities in rollups (00:46:55) Discussion on the potential for fraudulent rollups and the need for external validation.

Cryptography vs. politics in rollups vs. drive chains (00:48:40) Comparison of the role of cryptography and politics in rollups and drive chains.

Use of Bitcoin as a native token in Citrea (00:50:04) Explanation of the use of Bitcoin as a native token in Citrea and the decision to name it as “btc” to avoid confusion.

The Citrea Project (00:50:50) Discussion on the Citrea project’s features and compatibility with various virtual machines.

Future Research Endeavors (00:51:52) Exploration of decentralized sequencer network, consensus mechanisms, and trustless atomic swaps.

Lightning Integration (00:56:29) Discussion on the integration of Citrea with the Lightning Network and its significance.

User Onboarding and Experience (00:57:55) Explanation of the ease of onboarding, use of wallets, and the compatibility with Ethereum.

Citrea as a Blockchain (01:01:08) Explanation of Citrea as a blockchain and its differences from a sidechain.

Technical and Financial Benefits of Citrea (01:10:17) Comparison of transaction costs and user experience between Citrea and Bitcoin.

Revenue Model and Node Incentives (01:15:25) Discussion on revenue sharing, incentives for supporting the ecosystem, and the role of nodes in the Citrea project.

The incentive for people to support the trail (01:16:52) Discussion on the incentives for individuals to support the trail and the benefits of using Bitcoin for non-custodial and cheap transactions.

Target audience and use case for Citrea (01:17:53) Exploration of the target audience and use cases for Citrea, focusing on the desire to use Bitcoin for financial purposes without moving it to custody solutions.

Testing and open sourcing of Citrea (01:20:02) Information about the availability of testing, the internal developer net, and the roadmap for open sourcing the code base, including the Bitcoin bridge.

Following the project and contributing to Citrea (01:21:01) Details on how to follow the Citrea project, access documentation, and contribute to its development through the website, Twitter, and Discord.

Excitement for the future of Bitcoin and Citrea (01:22:52) Expression of enthusiasm for the potential of Bitcoin and the Citrea project, including plans for private swaps and investment opportunities.

The future of Bitcoin and the impact of Citrea (01:23:00) Reflection on the potential for innovation and change in the use of Bitcoin, with a focus on the impact of zero knowledge proof rollups and the potential for future developments.

Vlad Costea

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