Yinglei Song

1. Introduction Nowadays, images have become an important form of digital data that can accurately store a large amount of information. The contents in many images contain crucial information and thus need to be made available only to certain groups of individuals. The security of such images is generally improved by algorithms designed to encrypt images [1,2].

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1. Introduction With the rapid development of medical imaging technology, brain tumor image segmentation has made remarkable progress as an important medical image processing task. So far, two major types of brain tumors have been identified, including the primary and metastatic tumors based on whether the brain tumor cells are generated autonomously or migrate to the brain for generation [1].