Shadowsocks is a free and open-source encryption protocol project, widely used in China to circumvent Internet censorship. It was created in 2012 by a Chinese programmer named "clowwindy", and multiple implementations of the protocol have been made available since. Shadowsocks is not a proxy on its own, but (typically) is the client software to help connect to a third-party SOCKS5 proxy, which is similar to a Secure Shell (SSH) tunnel. Once connected, internet traffic can then be directed through the proxy. Unlike an SSH tunnel, shadowsocks can also proxy User Datagram Protocol (UDP) traffic.