Circumventing net censorship

Amid increasing censorship of internet sites by governments, Telex—created by computer security researchers from the universities of Michigan and Waterloo—is the latest approach to circumventing internet censorship. Telex seeks to place anticensorship technology into the internet's core network infrastructure through cooperation from large internet service providers (ISPs).

Telex focuses on avoiding detection by the censor. It allows a user to circumvent a censor without alerting the censor about the act of circumvention. Rather than replacing services like Tor, it seeks to complement them. The service employs deep-packet inspection—a technology sometimes used to censor communication—and repurposes it to circumvent censorship.

Other systems require distributing secrets such as encryption keys or IP addresses to individual users. If the censor discovers these secrets, it can block the system. However, with Telex, there are no secrets that need to be communicated to users, only the publicly available client software. Telex can provide a state-level response to state-level censorship.

Many anticensorship systems work by making an encrypted connection (called a 'tunnel') from the user's computer to a trusted proxy server located outside the censor's network. This server relays requests to censored websites and returns the responses to the user over the encrypted tunnel. This approach leads to a cat-and-mouse game. The censor attempts to discover and block the proxy servers.