# CrossDeFi: A Novel Cross-Chain Communication Protocol
## 1 Introduction
Achieving interoperability within the DeFi ecosystem involves overcoming challenges related to diverse protocols and standards, security, scalability in cross-chain communications, legal compliance across jurisdictions, and the inherent complexity of the task. The primary challenge in DeFi is ensuring the mobility of digital assets without them being locked in a particular network for too long. Introducing a cross-chain DeFi communication protocol effectively addresses these issues, facilitating broader adoption and enhancing the effectiveness of cross-chain transactions [22]. Ensuring transaction finality is also crucial as it guarantees that transactions are irreversible, mitigating the risk of double-spending and ensuring immutable transaction records [23]. However, traditional cross-chain strategies often fail to provide high interoperability with multiple types of assets and a reliable finality guarantee simultaneously. They also suffer from high transaction fees, long confirmation times, and security vulnerabilities, which hinder seamless cross-chain transactions [24]. For instance, the Metronome cross-chain solution introduces new attack vectors due to the complexity of its bridging mechanism [25]. Notably, the gas fees of decentralized liquidity protocols such as Kybernetwork [26] and BTC relay [27] are expensive during peak times, deterring DeFi users from executing trades. While these cross-chain solutions are innovative and enable cross-chain interoperability, they introduce novel security concerns and high operational costs, making them impractical for real-time DeFi deployments. Moreover, they lack support for multi-asset transactions. Typically, existing protocols use different cross-chain components, such as bridges, oracles, and wrapped tokens, to facilitate interactions across different blockchains. Bridges have become adaptable within DeFi systems due to their role in asset interoperability [28]. Each DeFi system may use different bridges to transfer various assets, making it crucial to select asset-specific bridges to optimize transfer speed and security [29]. Additionally, there is no effective cross-chain solution to handle asset diversity in transfer and ensure transaction finality within a heterogeneous DeFi system. Conventional cross-blockchain asset transfer solutions are customized and have notable design limitations, such as lacking multi-asset transfer support and faster transaction finalities, leading to real-time interoperability constraints and double-spending risks [25; 26; 27]. These limitations motivate the proposal of novel cross-chain solutions like CrossDeFi, which features asset-specific bridge selection and improved transfer confirmations to provide rapid multi-asset transfer support with minimal cost and protection against double-spending in a heterogeneous DeFi environment. Given these challenges, there is an urgent need for a new cross-chain protocol specifically designed to meet the needs of the DeFi ecosystem in terms of interoperability over diversified assets and transaction finality guarantees while addressing security, speed, and cost issues. Thus, this paper proposes CrossDeFi, a novel DeFi cross-chain protocol aimed at enhancing interoperability and ensuring the finality of asset transfers while maintaining the essential features of the DeFi system.