Image decryption device, image encryption device, image decryption method, and image decryption program

摘要

When a decrypting apparatus receives an encrypted image, the apparatus detects the state of the encrypted image and determines whether the encrypted image is an image passed through only a digital medium or an analog medium, according to the state of the encrypted image. When the encrypted image is determined to be the image passed through only the digital medium, the decrypting apparatus switches to perform a digital decryption process and, when the encrypted image is determined to be the image passed through the analog medium, the decrypting apparatus switches to perform an analog decryption process.