The Tor Project has transitioned from its longstanding bridge distribution system, BridgeDB, to a more advanced and flexible platform known as Rdsys. This move aims to enhance the network's resilience against evolving censorship tactics and improve overall user accessibility.
BridgeDB, introduced over a decade ago, functioned as a prototype to assist users in bypassing censorship by distributing bridge addresses — unlisted relays that facilitate access to the Tor network. Despite its initial success, BridgeDB faced challenges adapting to sophisticated censorship methods, leading to technical debt and maintenance difficulties. Recognizing these limitations, the Tor Project initiated the development of Rdsys approximately four years ago.
Rdsys, short for Resource Distribution System, is designed as a modular framework that separates components such as distribution logic and communication methods (e.g., email, Telegram). This architecture allows for rapid experimentation with new distribution channels and tools, enabling the system to swiftly adapt to emerging censorship threats. For instance, in response to increased censorship in Russia, Rdsys facilitated bridge distribution through Telegram, leveraging account history to differentiate genuine users from potential censors.
A significant improvement with Rdsys is the elimination of captchas, which were previously used in BridgeDB to verify legitimate users. Captchas often posed accessibility challenges for users with disabilities or those facing language barriers. Moreover, censors developed methods to bypass captchas, diminishing their effectiveness. By removing this obstacle, Rdsys enhances both the accessibility and reliability of
Tor bridges, ensuring a smoother user experience.
The
transition to Rdsys was completed in October 2024, with BridgeDB officially retired. This change is expected to be seamless for users, as the distribution mechanisms — such as web-based requests and the Tor Browser's built-in API — remain operational. However, users may notice the absence of captchas when obtaining bridge addresses, reflecting the improved user-friendly approach of Rdsys.
Looking forward, the Tor Project
plans to leverage Rdsys's modular design to introduce new anti-censorship tools and expand bridge distribution channels. The community is encouraged to participate by contributing to development efforts or operating Tor bridges, reinforcing the collective endeavor to maintain an open and accessible internet for all.
