Pepper: High-bandwidth and Scalable Anonymous Broadcast with Cryptographic Privacy

2026-06-02

AI Summary

This work addresses sender privacy in high-bandwidth, scalable anonymous broadcasting by proposing an efficient scheme based on a two-server DC-net architecture. The design incorporates a self-contained anonymous registration protocol that eliminates the need for external dial-up services, a batch messaging mechanism built upon distributed point functions, and a lightweight access control method grounded in secret-sharing-based proofs. By integrating cryptographic primitives such as verifiable distributed point functions, the system achieves millisecond-level registration auditing and supports scaling to thousands of channels. Experimental results demonstrate that the scheme improves effective message throughput by 1.2× to 20× compared to the current state-of-the-art solutions.

Abstract

We present Pepper, a high-bandwidth anonymous broadcast protocol that provides cryptographic sender anonymity against global adversaries. Pepper builds on a two-server DC-net architecture but introduces three key innovations: a self-contained anonymous registration subprotocol using verifiable distributed point functions, support for batch messaging via distributed multi-point functions, and a lightweight access control mechanism based on secret-shared proofs. Unlike prior systems, Pepper eliminates the need for external dialing services and allows each broadcaster to send multiple messages per epoch with a single audit, significantly improving throughput for large data transfers. Our implementation demonstrates that Pepper achieves millisecond-level registration audits, scales efficiently to thousands of channels, and delivers 1.2--20$\times$ higher effective messaging rates than state-of-the-art alternatives. Furthermore, Pepper is designed for practical deployment, with natural compatibility for co-deployment alongside Tor and federated social networks.

Problem

• anonymous broadcast
• cryptographic privacy
• high-bandwidth
• scalability
• global adversaries

Innovation

• anonymous broadcast
• verifiable distributed point functions
• batch messaging
• secret-shared proofs
• scalable privacy