Federated learning trains an AI model across many devices or organizations while sharing model updates instead of collecting all the raw data in one place. The distributed setup can make it vulnerable to backdoor attacks, in which specially prepared inputs cause the trained model to produce an attacker-chosen result.

The proposed method, called Federated Generative Adversarial Trigger, uses publicly available versions of the shared model and a small number of samples to generate attack patterns. A fixed, trained shared model guides the pattern generator, helping the resulting triggers match features learned by the global model rather than only those of an individual device.