Proving resistance to conventional attacks, e.g., differential, linear, and integral attacks, is essential for designing a secure symmetric-key cipher. Recent advances in automatic search and deep learning-based methods have made this time-consuming task relatively easy, yet concerns persist over expertise requirements and potential oversights. To overcome these concerns, Kimura et al. proposed neural network-based output prediction (NN) attacks, offering simplicity, generality, and reduced coding mistakes. NN attacks could be helpful for designing secure symmetric-key ciphers, especially the S-box-based block ciphers. Inspired by their work, we first apply NN attacks to Simon , one of the AND-Rotation-XOR-based block ciphers, and identify structures susceptible to NN attacks and the vulnerabilities detected thereby. Next, we take a closer look at the vulnerable structures. The most vulnerable structure has the lowest diffusion property compared to others. This fact implies that NN attacks may detect such a property. We then focus on a biased event of the core function in vulnerable Simon -like ciphers and build effective linear approximations caused by such an event. Finally, we use these linear approximations to reveal that the vulnerable structures are more susceptible to a linear key recovery attack than the original one. We conclude that our analysis can be a solid step toward making NN attacks a helpful tool for designing a secure symmetric-key cipher.

There exist Adversarial Examples (AEs) that intentionally misclassified images of neural networks to a different class. We propose a method of attack by AEs that uses lasers to facilitate control of misclassification. A previous work has shown that road signs can be misclassified by irradiating them with lasers. We focus on the effective attack in the situations that the attacker can prepare the road signs. Namely, in our attack, the attacker prepares the road signs made by using AEs with missing perturbation, and makes misclassified by using laser irradiation in effective. In this paper, we present principle and method for misclassifying the road signs made by the AEs with missing perturbation by using laser irradiation. In addition, we demonstrate the effectiveness of the proposed method by experiments.

The integral three-dimensional (3D) display is an ideal visual 3D user interface. It is a display method that fulfills many of the physiological factors of human vision. However, in integral 3D displays for mobile applications that use direct-view flat panels to display elemental images, color moiré is a problem that occurs because of the sampling of subpixels by elemental lenses and the insufficient resolution and depth reproduction of the reconstructed 3D image. In the conventional moiré reduction method, the degree of defocus of elemental lenses has to be set to a large value, which is one of the factors that reduces the performance in terms of depth reproduction. In contrast, only one-step optics can be installed and the installation positions are limited in the conventional wobbling method. This is because, in the method, which uses a birefringent optical element, two-step optics are thicker than the focal length of the lens array. For this reason, it was difficult to achieve ideal moiré reduction and depth reproduction performance improvements. To solve these problems, we propose a method that utilizes multiple optical wobbling spatiotemporal multiplexing using polarization diffractive elements and liquid-crystal polarization controllers. Using the proposed method, the wobbling optics can be designed to be thin, allowing two-step optics to be installed between the display panel and lens array. When the moiré modulation degree without wobbling is normalized as 100%, it decreases to 25% with wobbling. The proposed method not only achieves effective color moiré reduction without deteriorating the 3D image quality, but also can double the resolution of the elemental images to improve the depth reproduction.

The integral three-dimensional (3D) display is an ideal visual 3D user interface. It is a display method that fulfills many of the physiological factors of human vision. However, in integral 3D displays for mobile applications that use a direct viewing flat panel to display elemental images, the occurrence of color moiré is a problem owing to the sampling of subpixels by the elemental lenses and the insufficient resolution and depth reproduction performance of the reconstructed 3D image. We propose a method to solve these problems that utilizes optical wobbling spatiotemporal multiplexing using a birefringent element and a polarization controller. With the conventional moiré reduction method, the degree of defocus of el-ementallenses has to be set to a large value, which has also been a factor that reduces the depth reproduction performance. We show that effective color moiré reduction can be achieved with a slight defocus of elemental lenses and without deteriorating depth reproducibility by using the proposed optical wobbling method.