We consider a collaborative learning scenario in which multiple data-owners wish to jointly train a logistic regression model, while keeping their individual datasets private from the other parties. We propose COPML, a fully-decentralized training framework that achieves scalability and privacy-protection simultaneously. The key idea of COPML is to securely encode the individual datasets to distribute the computation load effectively across many parties and to perform the training computations as well as the model updates in a distributed manner on the securely encoded data. We provide the privacy analysis of COPML and prove its convergence. Furthermore, we experimentally demonstrate that COPML can achieve significant speedup in training over the benchmark protocols. Our protocol provides strong statistical privacy guarantees against colluding parties (adversaries) with unbounded computational power, while achieving up to $16\times$ speedup in the training time against the benchmark protocols.

该研究提出了COPML算法，这是一个完全去中心化的训练框架，可以保护数据隐私并实现可伸缩性，使用对个体数据进行安全编码的方式在多方之间分发计算负载，并以分布式方式执行训练计算和模型更新。实验演示了COPML相较于基准协议在训练速度上可实现高达16倍的加速。

隐私保护协作机器学习的可扩展方法