A recording device which is capable of preventing alteration of a generated digital picture data and suitable for improving the reliability of the digital picture data as an evidence. The recording device includes a related information embedding unit for embedding a related information on the digital picture data stored in a related information storing unit in the digital picture data obtained by a picture receiving unit by means of the digital watermarking technique, a digital signature generating unit for generating a digital signature of the digital picture data in which the related information has been embedded, and a recording unit for adding the digital signature to the digital picture data in which the related information has been embedded and storing it in a memory unit.