Improving Directed Acyclic Graph-Based IoT Consensus through a Hybrid Stake-Weighted Fast Probabilistic Consensus Framework

Abstract

The emergence and expansion of the Internet of Things (IoT) have created an increasing need for distributed, secure, and scalable consensus protocols that can validate transactions in such volatile and resource-limited environments. DAG-based ledger systems, in combination with Fast Probabilistic Consensus (FPC) offer high throughput with minimal communication cost for conflict resolution. However, traditional FPC does not have any logical means of assigning weight to different validators in an adversarial setting. In this context, this article attempts to present a hybrid Proof-of-Stake and Fast Probabilistic Consensus (PoS-FPC) protocol for DAG-based IoT systems. The proposed framework consists of transaction attachments on a DAG graph, Ed25519 signatures, BLAKE2b-256 hashing, a weighted quorum for non-conflicting transactions, and a stake-weighted FPC algorithm for the resolution of conflicting transactions. The weight of validators in the proposed framework is computed based on an adaptive weighting scheme that uses the normalized weight of stake and mana, dynamically tunes their weights depending on network traffic, and implements reward and penalty mechanisms to ensure honest participation and prevent malicious attacks. The proposed framework was tested by conducting discrete event simulations of 20,000 transactions in different adversarial situations. The experimental evaluation yielded a throughput of 5,128 transactions per second, a decision accuracy of 99.6%, adversary resistance of 97.81%, a quorum latency of 69.782 ms, FPC conflict latency of 690 ms and average convergence time of 3.73 rounds of the FPC algorithm. When compared to a mana-based DAG-FPC framework that was evaluated under the same simulation setup, the proposed framework outperforms it in terms of decision accuracy, conflict latency, faster convergence, and robustness to adversarial participation of up to 40%.