Fortalecendo a privacidade e segurança em VPN: explorando blockchain e prova de conhecimento zero como solução

Abstract

Data privacy has become a central concern for users with the increased use of digital technologies and online platforms. Virtual Private Networks (VPNs) have emerged as a popular solution to protect this privacy. However, even with the use of VPNs, there are still ways in which users’ privacy can be compromised, especially in authoritarian regimes where data exposure can lead to political persecution. Additionally, VPNs face privacy risks due to security breaches and data leaks caused by hacker attacks or abusive judicial orders. These vulnerabilities highlight the urgent need to develop a more robust solution that ensures anonymity and privacy for users in such adverse situations. In this context, the main objective of this study is to develop and evaluate an anonymous authentication architecture for VPN services using blockchain technologies and zero-knowledge proof (ZKP), aiming to enhance user privacy and security in various threat scenarios. The methodological approach adopted follows the principles of Design Science Research (DSR), focusing on the development and evaluation of a technological artifact that integrates VPN with blockchain and ZKP. The integration of blockchain and ZKP prevents the storage of sensitive data, while the use of cryptocurrencies eliminates the need to record payment information, a common vulnerability point. The proposed solution has the potential to prevent leaks of personally identifiable information and is especially relevant for journalists, activists, and citizens in oppressive regimes who need reliable tools to protect their online identities. The implementation developed in this work, based on the Ethereum blockchain, confirmed the feasibility of the artifact. The transaction fees were around $4.21, with most of the cost associated with the deployment of the smart contract. For VPN service renewal, this cost would drop to about $0.48, as there would be no need to generate a new contract. The ZKP-based authentication, with encryption in the communication channel, achieved an average time of 3.27 seconds, reinforcing the feasibility of the solution.