DeCoTa: a lightweight decentralized cross-chain transfer scheme based on hash-locking.

With the wide application of blockchain comes the challenge of cross-chain interaction. For example, the isolation between the information stored in different blockchains can result in the "isolated islands of value" effect in blockchains. In addition, conventional cross-chain methods have a number of drawbacks such as centralization, or have a very restricted application scope. (e.g., hash-locking can only be utilized for asset exchanges, but asset transfer is a more common and demanding requirement). Other solutions like sidechain may be an overkill (e.g., too complex) for simple applications. To address these challenges, we propose an cross-chain transaction scheme that integrates hash-locking with notary mechanisms to enable decentralized asset transfers. By embedding notary scheme within the hash-lock structure, our approach ensures support for asset transfers while mitigating centralization risks. Additionally, we enhance the traditional hash-locking mechanism, making it more flexible and suitable for diverse cross-chain scenarios. This combination of hash-locking and notary scheme allows our scheme to overcome the original shortcomings of them both, while maintaining high efficiency and security. In addition to designing the transaction method, we also constructed a transaction model, conducted experiments on transaction gas consumption, performed a detailed security analysis, and presented an in-depth discussion of our scheme while proposing directions for future work. Experiment and analysis demonstrate the practicability of our scheme in terms of performance and security.