Provided is an information processing device including a data processing unit that executes reproduction processing of content recorded in an information recording medium. The content includes an individual segment region formed of a plurality of variation data in which identification information different from each other is embedded and each of which can be decrypted by a different key, and a common segment region formed of single data. The variation data is formed of a 6144 byte aligned unit. The data processing unit calculates a reproduction path by applying a device key held in a memory, and selects an aligned unit corresponding to one variation data that corresponds to the calculated reproduction path from a plurality of aligned units configuring the plurality of variation data in the individual segment region included in the data read from the information recording medium, and then, executes the decryption and reproduction processing.

Provided is an information processing device including: a data processing unit that performs a content playback process; and a communication unit that communicates with a server, wherein the content is content that has a segment region configured with a plurality of pieces of variation data which can be respectively decrypted by different keys, and for which a plurality of playback paths can be configured according to variation data which is selected as a playback object, wherein each piece of variation data is data for which a variation data identifier can be analyzed from decrypted data, and wherein the data processing unit receives playback path information which is allowed to be played from the server through the communication unit, and selects variation data from the segment region so as to perform content playback, according to the playback path information received from the server.

A method for content playback and recording may include using a computer to obtain media content from a recorded medium. Concurrently with obtaining the media content, the method may include reencrypting the encrypted media content using a secondary encryption key and storing the reencrypted media content in a storage device.