Pyros: A state channel-based access control system for a public blockchain network

Abstract

Blockchain is a technology that enables the implementation of a decentralized system by replacing the role of the centralized entity with the consensus of participants in the system to solve the problem of subordination to the centralized entity. Blockchain technology is being considered for application in numerous fields; however, the scalability limitation of a public blockchain has led many researchers to consider private blockchains, which reduce the security of the system while improving scalability. A state channel represents a leading approach among several scalability solutions, intended to address public blockchain scalability challenges while ensuring the security of the blockchain network. Participants in the channel perform the process of updating the state of the channel outside the blockchain. This process can proceed very quickly because it does not require the consensus of the blockchain network, but still, like on-chain, it can guarantee features such as irreversibility. In this paper, we propose the PyRos protocol, an access control system that supports the trading and sharing of data between individuals on a public blockchain based on the state channel. As far as we know, the research using the off-chain state channel for access control has not been proposed yet, so PyRos is a new approach in this field. In PyRos, user-defined access control policies are stored off-chain, and policy updates are always rapid regardless of the performance of the blockchain network. Moreover, PyRos provides means to prevent malicious participants from arbitrarily using the channel's previous state while resolving constraints due to scalability problems, along with privacy guarantees for the transaction content. To evaluate the efficiency and security of PyRos, we provide qualitative analysis of security requirements and analysis in terms of the performance of public blockchain platforms.