NEURAL STYLE TRANSFER BASED SLIDER PUZZLE CAPTCHA

Two CAPTCHA variants based on neural style transferred image are described: an option-based CAPTCHA and a slider-based CAPTCHA. In the neural style transfer-based slider puzzle CAPTCHA, a neural style transferred image is used as the background. Multiple missing blocks and a puzzle block to be moved are embedded on the neural style transferred image. The user is presented with a slider, using which they can drag the sliding block and place it on the correct missing block. Since the background image is neural style transferred, it becomes difficult to decipher the original image due to high difference in the texture. Placing multiple missing blocks makes the system more resilient to attacks because the chances of finding the correct missing block position is decreased. In the option-based neural style transfer image CAPTCHA, a neural style transferred image of an object/animal is presented to the user along with multiple options. The user is asked to select the option that best describes the presented image. A neural style transferred image helps the CAPTCHA to be more resilient to automated attacks, since the ability of image being reverse searched and answered is less.