Achieve Thumbnail Preserving Encryption by Sum Preserving Approaches for Images

A large number of images are generated and uploaded to the cloud, due to the rapid development of IT and networking technologies. To prevent unauthorized access, image encryption is a way that can ensure the safety of images. However, the encrypted image is noisy, which is not suitable for further management and application. Some scholars have recently proposed the concept of Thumbnail Preserving Encryption (TPE). The encrypted image not only achieves privacy protection, but also preserves the properties of thumbnails. Therefore, when an image is encrypted by TPE, it is possible for the thumbnail image to retain similar appearance after encryption, allowing a quick overview of the encrypted image. In this paper, we propose a new TPE method to resolve the problems that may arise in methods used by cryptography scholars such as Tajik. Experimental results show that our TPE method retained the same thumbnail appearance before and after encryption.