Provided is imparting authentication codes to image data photographed by a camera connected to the apparatus for recording and reproducing images to generate encryption data and monitors control instructions input from the outside to the apparatus for recording and reproducing images, thereby interrupting the control instructions that store or cancel the image data stored in the apparatus for recording and reproducing images. As a result, the integrity of the image data cannot be questioned. Further, when the image data stored in the apparatus for recording and reproducing images are submitted as evidence, the integrity of the image data and the information on the corresponding image data submitted as evidence can be verified by using the authentication data generated for the original image data.