What is Citrea?
Citrea pioneers a groundbreaking rollup solution that amplifies the capabilities of Bitcoin blockspace using zero-knowledge technology, opening up possibilities for comprehensive development on the Bitcoin network. Notably, this innovation requires no alterations to the network's consensus rules.
Functioning as a Type 2 zkEVM, Citrea efficiently processes numerous zkEVM transaction batches, producing succinct zero-knowledge proofs. These proofs encapsulate the validity of each batch and are inscribed into the Bitcoin blockchain through inscription-like envelopes.. By regularly publishing these proofs to Bitcoin, Citrea ensures transparent and secure verification of its operations.
The inscribed Citrea proofs in the Bitcoin blockchain are optimistically verified through BitVM, enabling any Bitcoin node operator to both verify Citrea's transactions and access its complete state. This approach ensures that the necessary data for transacting on or validating Citrea becomes readily available to every participant within the Bitcoin network. Additionally, by regularly publishing validity proofs to Bitcoin and optimistically verifying them, Citrea becomes the only Layer 2 that uses the Bitcoin Network both data availability and settlement layer.
How does Citrea support the Bitcoin ecosystem?
- EVM Compatibility: Citrea enables Bitcoin to seamlessly integrate with the Ethereum Virtual Machine (EVM) and its surrounding ecosystem by utilizing BTC as Gas, thereby enhancing compatibility and interoperability between the two networks. Citrea uses $BTC as its native token. To avoid confusion and improve on/off-ramp UX; Citrea native $BTC is referred to as $cBTC in Citrea.
- The First Universal Trust-minimized Two-way Peg: Citrea's light client proofs are directly verified on the Bitcoin network through BitVM, marking a significant milestone as the first layer 2 verification within Bitcoin and introducing a trust-minimized two-way peg mechanism. The BTC pegged to Citrea is securely held within the BitVM contract on the Bitcoin network, leveraging the Taproot technology. Withdrawals are exclusively authorized with valid zero-knowledge proofs (ZK proofs), ensuring that no entity can unlawfully access or misappropriate the pegged BTC from the bridge.
- Validity: Citrea generates a zero-knowledge proof for each batch of transactions within its zero-knowledge EVM, resulting in a concise zero-knowledge proof that outputs a state difference of the batch, and the blockhash of Bitcoin block that the batch is built on.. This proof is then inscribed on the Bitcoin blockchain, ensuring accessibility to all participants within the network, including light nodes (SPVs) and Bitcoin scripts, via BitVM.
- Data Availability: Citrea's proofs yield the state difference of each batch, with these proofs and outputs inscribed on the Bitcoin blockchain. By scanning these proofs within Bitcoin blocks, individuals can construct the most recent state tree of the rollup, ensuring essential transaction data remains consistently accessible on Bitcoin.
- Censorship Resistance: Citrea employs forced transaction envelopes akin to inscriptions on the Bitcoin main chain. This allows any user to submit a Citrea transaction to Bitcoin using a specified encoding. Citrea's circuit guarantees the inclusion of every forced transaction in the subsequent batch via inclusion and soundness proofs within the corresponding Bitcoin block they are included in.
- Re-org Resistance: Citrea incorporates the most recently finalized Bitcoin block hash into the rollup block header. Once the corresponding proof for the rollup block is transmitted to Bitcoin and finalized, it becomes resistant to re-org without simultaneously re-orging the Bitcoin blockchain itself. This level of resistance is nearly insurmountable after 6 blocks of confirmation.
What are the main use cases that Citrea supports?
- DeFi
- NFTs
- Gaming
- DAOs
- Inscription
- Privacy Apps
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