Cross-Consensus Reliable Broadcast and its Applications
Yue Huang
Network and Distributed System Security (NDSS) Symposium 2026 · Day 3 · Systems Security
Modern distributed infrastructures are moving beyond isolated consensus islands toward multi-group coordination architectures -- sharded blockchains, cross-chain bridges, and replicated state machines. This talk introduces **Cross-Consensus Reliable Broadcast (CrossRBC)**, the first formal treatment of how groups with their own consensus protocols can reliably communicate with each other. The researchers present three protocol constructions with increasing efficiency, culminating in **CrossRBC-SIG** -- the first cross-consensus protocol **decoupled from source group size**, enabling scalable interconnection of thousands of shards or chains.
AI review
A solid distributed systems theory contribution formalizing cross-group consensus communication. The three protocol constructions are clean and the complexity improvements over baselines are significant. However, this is distributed systems research, not security research -- no attacks, no exploits, no vulnerability analysis. The cross-chain bridge application has the most security relevance but is treated as a deployment scenario rather than a security analysis.