Pepper: High-bandwidth and Scalable Anonymous Broadcast with Cryptographic Privacy
2026-06-03 • Cryptography and Security
Cryptography and Security
AI summaryⓘ
The authors introduce Pepper, a new communication system that lets people send anonymous messages quickly and securely, even if someone is watching everything. It improves on previous systems by allowing users to register anonymously on their own and send multiple messages at once without slowing down the process. Pepper also includes a simple way to control who can send messages, making it practical and efficient for large-scale use. Their tests show that Pepper works much faster than other similar tools and can easily fit with services like Tor and social networks.
anonymous broadcastDC-netverifiable distributed point functionsmulti-point functionsaccess controlcryptographic anonymitymessage batch processingglobal adversariesTorfederated social networks
Authors
Chenghao Li, Haoyuan Wang, Xianghang Mi
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.