CRSA: A Cryptocurrency Recovery Scheme Based on Hidden Assistance Relationships

As cryptocurrency and blockchain-related assets become more common in our digital society, there is a corresponding need to secure our digital assets, including the private keys used to secure access to such assets (e.g., due to loss or corruption of the data storage medium). However, there are limitations in existing blockchain-related asset management and recovery methods. Therefore, we use zero-knowledge proof to design a cryptocurrency recovery scheme based on hidden assisting relationships (hereafter referred to as the CRSA scheme) to facilitate the recovery of blockchain assets. Specifically, when the user’s private key is lost, and access to the assets cannot be obtained, the user leverages information such as the pre-defined list of assistants to authenticate himself/herself on the blockchain. Once the assistants have confirmed the legitimacy of the user’s authentication request, the asset will be transferred from the old address to the new address. During the (identity) proof process, the zero-knowledge proof is used to ensure that the identification of assistants is not leaked to other nodes, assistants, and the adversary. We provide the formal definition of the above scheme and the security proof of the construction. We also implement a prototype of the system and evaluate its performance. Evaluations indicate that the time required for the zero-knowledge proof is less than 10s, and the block verification time is less than 100ms.