Decentralized Hierarchical Authorized Payment with Online Wallet for Blockchain

In Bitcoin, the knowledge of private key equals to the ownership of bitcoin, which occurs two problems: the first problem is that the private key must be kept properly, and the second one is that once the private key is given, it can’t be taken back, hence the bitcoin system can only implement the transfer function. In this paper, we first propose a new digital signature algorithm and use it to design an online wallet, which can help the user derive the signature without obtaining the user’s private key. Secondly, using our proposed online wallet, we extend the application of private key so that the cryptocurrency system can implement the authorization function. In more detail, we define a new primitive that we call decentralized hierarchical authorized payment scheme (DHAP scheme). We next propose a concrete instantiation and prove its correctness. Finally, we analyze the security and usability of our scheme. For security, we prove our scheme to be secure under the random oracle model. For usability, we examine its performance and compare it with bitcoin’s performance.