According to an embodiment, an information processing device includes: an extracting unit configured to extract a feature quantity of a content; a first detecting unit configured to detect a point in the content where variation of the feature quantity is a first predetermined amount or more; a second detecting unit configured to detect components of watermark information including components corresponding to respective intervals based on the point; a determining unit configured to determine a reliability of the watermark information that is detected; and a selecting unit configured to select a first watermark information from the watermark information based on a result of determination determined by the determining unit.