Tithonus: A Bitcoin Based Censorship Resilient System
This addresses the problem of enabling reliable and surreptitious communications for users in censored environments, representing a novel method rather than an incremental improvement.
The paper tackles the problem of providing censorship-resistant communication in the presence of state-level censors by introducing Tithonus, a framework that leverages the Bitcoin blockchain and peer-to-peer gossip protocol, resulting in a cost reduction of 2 orders of magnitude and a goodput increase of 3 to 5 orders of magnitude compared to state-of-the-art Bitcoin writing solutions.
Providing reliable and surreptitious communications is difficult in the presence of adaptive and resourceful state level censors. In this paper we introduce Tithonus, a framework that builds on the Bitcoin blockchain and network to provide censorship-resistant communication mechanisms. In contrast to previous approaches, we do not rely solely on the slow and expensive blockchain consensus mechanism but instead fully exploit Bitcoin's peer-to-peer gossip protocol. We develop adaptive, fast and cost effective data communication solutions that camouflage client requests into inconspicuous Bitcoin transactions. We propose solutions to securely request and transfer content, with unobservability and censorship resistance, and free, pay-per-access and subscription based payment options. When compared to state-of-the-art Bitcoin writing solutions, Tithonus reduces the cost of transferring data to censored clients by 2 orders of magnitude and increases the goodput by 3 to 5 orders of magnitude. We show that Tithonus client initiated transactions are hard to detect, while server initiated transactions cannot be censored without creating split world problems to the Bitcoin blockchain.