To prevent leakage of an encryption key or a decoding key in an information processor for encrypting and storing information.

A control part 11, an operating part 12, a communication part 13, a management part 14 and an image reading part 17 being configuring elements for realizing the function of a printer device 1 being an information processor are respectively provided with storage areas 111, 121, 131, 141 and 171 configured of an ROM, and the storage areas 111, 121, 131, 141 and 171 are made to store split information (a), b, c, d and e. The control part 11 generates the encryption key by using the plurality of pieces of split information in a predetermined timing, and encrypts image data by using the generated encryption key, and stores the image data in a storage part 16, and decodes the image data by using the encryption key as a decoding key, and outputs the image data. Also, the control part 11 erases the generated encryption key in a predetermined timing so as to make it difficult to extract the encryption key to the outside.

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