The Greenest Way to Get Through the Great Firewall of China? An Energy Audit of Common Circumvention Tools Against the Great Firewall

In China, the Great Firewall of China (GFW) blocks or restricts access to various online content and services. To access the Internet without restrictions, many Chinese netizens use circumvention tools that employ encryption and obfuscation techniques to evade detection and filtering of the GFW, which increase the energy consumption of the devices and servers involved. This paper aims to compare the energy efficiency of five common circumvention tools: WireGuard VPN, Shadowsocks, V2ray, Xray, and Trojan-Go. An energy audit is conducted for each tool by measuring the energy consumption on the client side when downloading a specific file from a target server. Based on the empirical results, WireGuard VPN was recommended as the most energy-efficient tool, while Shadowsocks and WireGuard VPN both ranked the highest in the comprehensive score considering both energy and time consumptions.