1. An information processing device comprising: a memory that stores a history of performing, on an image having an attribute, a process that conceals an area within the image; a receiving unit that receives an image; a decision unit that extracts from the memory a history of a process performed on an image having an attribute that matches an attribute of the received image, and on the basis of the extracted history of a process, decides a concealment area within the received image; and a concealment unit that conceals the concealment area decided by the decision unit.