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Physical Black-box Adversarial Attacks through Transformations

—Deep learning has shown impressive performance in numerous applications. However, recent studies have found that deep learning models are vulnerable to adversarial attacks, where the attacker adds imperceptible perturbations into benign samples to induce misclassiﬁcations. Adversarial attacks in the digital domain focus on constructing imperceptible perturbations. However, they are always less effective in the physical world because the perturbations may be destroyed when captured by the camera. Most physical adversarial attacks require adding invisible adversarial features (e.g., a sticker or a laser) to the target object, which may be noticed by human eyes. In this work, we propose to employ image transformation to generate more natural adversarial samples in the physical world. Concretely, we propose two attack algorithms to satisfy different attack goals: Efﬁcient-AATR employs a greedy strategy to generate adversarial samples with fewer queries; Effective-AATR employs an adaptive particle swarm optimization algorithm to search for the most effective adversarial samples within the given the number of queries. Extensive experiments demonstrate the superiority of our attacks compared with state-of-the-art adversarial attacks under mainstream defenses.