Stake-based aggregation mechanism for FL with blockchain. In each round, the proposers are randomly selected from the participating clients to perform local training and upload local updates to the blockchain. Then, voters download the aggregated local updates from the blockchain, perform local validation, and vote for acceptance or rejection. If the majority of voters vote for accepting the global aggregation, the global model will be updated, and the proposers and the voters who vote for acceptance will be rewarded. Conversely, if the majority of voters vote for rejection, the global model will not be updated, and the proposers and the voters who vote for acceptance will be slashed.

Blog

October 2, 2024

Publication

Defending Against Poisoning Attacks in Federated Learning with Blockchain

March 18, 2024

Dong, Nanqing; Wang, Zhipeng; Sun, Jiahao; Kampffmeyer, Michael Christian; Knottenbelt, William; Xing, Eric.

Paper abstract

In the era of deep learning, federated learning (FL) presents a promising approach that allows multiinstitutional data owners, or clients, to collaboratively train machine learning models without compromising data privacy. However, most existing FL approaches rely on a centralized server for global model aggregation, leading to a single point of failure. This makes the system vulnerable to malicious attacks when dealing with dishonest clients. In this work, we address this problem by proposing a secure and reliable FL system based on blockchain and distributed ledger technology. Our system incorporates a peer-to-peer voting mechanism and a reward-and-slash mechanism, which are powered by on-chain smart contracts, to detect and deter malicious behaviors. Both theoretical and empirical analyses are presented to demonstrate the effectiveness of the proposed approach, showing that our framework is robust against malicious client-side behaviors.