Obelia: Scaling DAG-Based Blockchains to Hundreds of Validators

TL;DR

Obelia is a scalable DAG-based blockchain protocol that efficiently supports hundreds of validators by introducing a two-tier validator system, maintaining performance and robustness even with unreliable auxiliary validators.

Contribution

Obelia presents a novel two-tier validator architecture that enhances scalability and resilience of DAG-based proof-of-stake protocols without added overhead.

Findings

Supports hundreds of validators with no performance overhead.

Maintains robustness despite auxiliary validators being unreliable.

Seamlessly integrates with existing protocols.

Abstract

Obelia improves upon structured DAG-based consensus protocols used in proof-of-stake systems, allowing them to effectively scale to accommodate hundreds of validators. Obelia implements a two-tier validator system. A core group of high-stake validators that propose blocks as in current protocols and a larger group of lower-stake auxiliary validators that occasionally author blocks. Obelia incentivizes auxiliary validators to assist recovering core validators and integrates seamlessly with existing protocols. We show that Obelia does not introduce visible overhead compared to the original protocol, even when scaling to hundreds of validators, or when a large number of auxiliary validators are unreliable.