CensorLess: Cost-Efficient Censorship Circumvention Through Serverless Cloud Functions

TL;DR

CensorLess introduces a serverless-based censorship circumvention proxy that significantly reduces costs by 97% while maintaining robust censorship resistance through dynamic bridge rotation.

Contribution

It presents a novel serverless platform-based approach for censorship circumvention that outperforms existing methods in cost efficiency and robustness.

Findings

Reduces circumvention costs by 97% compared to prior techniques.

Maintains continuous connectivity through live migration.

Employs bridge rotation for enhanced censorship resistance.

Abstract

With the increase in Internet censorship globally, various circumvention tools have been designed and developed. However, the monetary cost of these tools deeply impacts both user choice and the sustainability of provider operations. Recent developments in censorship circumvention research attempted to achieve cost efficiency by utilizing Infrastructure-as-a-Service (IaaS) spot instances as bridges, but still incurred substantial expenses related to network connectivity and instance maintenance. In this work, we present CensorLess, a circumvention proxy built leveraging the unique benefits of a serverless platform. CensorLess comprises three components: a local proxy that handles client-side communication and ensures compliance with serverless functions' security restrictions, a function refresher that periodically regenerates bridges, and a live migration mechanism that maintains continuous connectivity. CensorLess inherits the serverless platform's cost efficiency, ephemerality, scalability, concurrency, and performance. Compared to existing low-cost, state-of-the-art circumvention techniques, CensorLess reduces costs by 97%, while simultaneously enabling robust censorship resistance by employing bridge rotation.