论文标题
辍学并不是您防止梯度泄漏所需的全部
Dropout is NOT All You Need to Prevent Gradient Leakage
论文作者
论文摘要
对联邦学习系统的梯度反转攻击从交换的梯度信息中重建客户培训数据。为了防止这种攻击,提出了各种防御机制。但是,它们通常会导致隐私和模型效用之间的不可接受的权衡。最近的观察结果表明,如果添加到神经网络中,辍学可以减轻梯度泄漏并改善模型实用程序。不幸的是,这种现象尚未系统地研究。在这项工作中,我们彻底分析了辍学对迭代梯度反转攻击的影响。我们发现,由于模型训练期间辍学引起的随机性,最先进的攻击状态无法重建客户数据。尽管如此,我们认为,如果在攻击优化期间对辍学引起的随机性进行了充分的建模,则辍学者不会提供可靠的保护。因此,我们提出了一种新型的辍学反转攻击(DIA),该攻击(DIA)共同优化了客户数据和辍学蒙版,以近似随机客户模型。我们对我们对四个开创性模型架构的攻击以及增加复杂性的三个图像分类数据集进行了广泛的系统评估。我们发现,我们提出的攻击绕过了似乎是由辍学引起的保护,并以高保真度重建客户数据。我们的工作表明,不能仅仅假定对模型体系结构进行更改的隐私变化可靠地保护梯度泄漏,因此应与补充防御机制结合使用。
Gradient inversion attacks on federated learning systems reconstruct client training data from exchanged gradient information. To defend against such attacks, a variety of defense mechanisms were proposed. However, they usually lead to an unacceptable trade-off between privacy and model utility. Recent observations suggest that dropout could mitigate gradient leakage and improve model utility if added to neural networks. Unfortunately, this phenomenon has not been systematically researched yet. In this work, we thoroughly analyze the effect of dropout on iterative gradient inversion attacks. We find that state of the art attacks are not able to reconstruct the client data due to the stochasticity induced by dropout during model training. Nonetheless, we argue that dropout does not offer reliable protection if the dropout induced stochasticity is adequately modeled during attack optimization. Consequently, we propose a novel Dropout Inversion Attack (DIA) that jointly optimizes for client data and dropout masks to approximate the stochastic client model. We conduct an extensive systematic evaluation of our attack on four seminal model architectures and three image classification datasets of increasing complexity. We find that our proposed attack bypasses the protection seemingly induced by dropout and reconstructs client data with high fidelity. Our work demonstrates that privacy inducing changes to model architectures alone cannot be assumed to reliably protect from gradient leakage and therefore should be combined with complementary defense mechanisms.