Anonymous User Registration in Online Forums Using Advanced Cryptographic Tumbling Inspired by Bitcoin Mixers and Server-Hosted Mnemonics: A Comprehensive Self-Hosted Implementation

This paper introduces a novel protocol for anonymous user registration in self-hosted online forums, designed to counter the pervasive data collection endemic to surveillance capitalism. This system uniquely combines a ”registration tumble,” a multi-party protocol inspired by the WabiSabi Bitcoin CoinJoin scheme, with a robust, user-friendly recovery mechanism based on server-hosted mnemonic shares. The registration tumble ensures that the server cannot link a user’s network identity to their final, issued credential, providing strong, unlinkable anonymity. The recovery system leverages Shamir’s Secret Sharing to split a user’s BIP-39 mnemonic, allowing the server to store an encrypted share for disaster recovery without ever having access to the user’s full key. We present a full-stack implementation using a containerized Flask and Nginx architecture, demonstrating its practicality for the self-hosting community. Performance benchmarks on both an AMD Ryzen 7 5700G and a Raspberry Pi 4 cluster show that our protocol achieves practical latencies for registration and recovery while remaining computationally feasible on low-cost hardware. A rigorous security analysis under a Dolev-Yao-style threat model confirms the protocol’s guarantees of anonymity, unlinkability, and credential security.