A Cryptocurrency Recovery System Based On Multi-party Authentication

With the growing popularity of blockchains and encrypted cryptocurrencies,public-private keys based on asymmetric encryption are widely used by blockchain systems.As the sole credential to control the asset,the private key is kept by the user,which avoids the possibility of the system infringing the user's assets.But it also brings the problem.The traditional centralized system can verify the user's identity and restore its assets when the user loses the private key(or password).However,in the decentralized system,once the user loses the private key,the assets will never be available.The wallet used to store the private key is not reliable,and private key loss events are endless.Various protection methods for private keys cannot fundamentally eliminate the problem of private key loss,which is why most people cannot accept cryptocurrencyA Cryptocurrency Recovery System Based on Multi-party Authentication(CRSMA)implements the asset recovery function under the private key for the problem that the blockchain asset is not available due to the loss of the private key.An identity authentication method in a decentralized environment is provided by establishing a communication channel between the user and the decentralized node(miner).First of all,the user pre-defines some secure channels as an identification medium.After losing the private key,the system will randomly select multiple miners to generate challenges through the consensus mechanism,which can avoid the centralization of the verifier.Then,the user collects the challenges through the channel and submits them to the blockchain,which has the same security as the traditional password recovery method.Finally,after ensuring that only the correct user is able to receive the information,the blockchain verifies the challenge submitted by the user and restores the asset.The system solves the problem of digital asset recovery,and makes the information of each stage of the recovery process public in the block,making it difficult for each party participating in the verification to do evil.In addition,the relationship between hacker attack probability and attack cost is analyzed by establishing an attack tree model,which proves the security of the system.Finally,the practicality of the solution is evaluated by implementing a system prototype.The prototype implementation can restore assets safely and efficiently on Ethereum,and has little effect on the execution efficiency of the original system.The processing time is in the millisecond level,and the cost of restoring the assets is three times that of the ordinary transaction.