There is provided an optical medium reproducing device configured to optically reproduce an optical medium including a plurality of tracks formed, the optical medium reproducing device including: an optical filter configured to receive an incident returned light beam from the optical medium, and to spatially and optically form a plurality of signals having different bands in a tangential direction and a radial direction; an arithmetic unit configured to operate the plurality of first signals formed by the optical filter so as to form a plurality of channels of second signals; and an electrical filter configured to individually receive the second signals, and to perform processing to the second signals so as to acquire a reproduced signal.

An optical disc including at least three layers of recording layers that each record information in an information track. The recording layer includes: an inner circumferential side region positioned on the inner circumferential side; a data region which is positioned to the outer circumferential side of the inner circumferential side region and records content information; and an outer circumferential side region positioned to the outer circumferential side of the data region. The content information is recorded in the data region of the three or more layers, and a point on an upper layer and a point on a lower layer one layer below the upper layer at which playback switches from content information of the upper layer being played back in an inner circumferential direction to content information of the lower layer, are set to be more to the outside than an innermost circumferential position of the data region.

Disclosed are techniques and systems for manufacturing an optical disc having a stochastic (i.e., non-deterministic) anti-piracy feature in the form of a multi-spiral structure, and for verifying the feature on the optical disc to authenticate the disc for playback. The multi-spiral structure may be comprised of multiple partially interleaved, and partially overlapping, spiral data tracks formed in a designated area of the optical disc. A process of forming the multi-spiral structure may include forming, in the designated area, a first spiral data track with first track pitch and a second spiral data track with second track pitch that is different than the first track pitch. The multi-spiral structure may be analyzed to determine verification parameters for verifying the multi-spiral structure, and those verification parameters may be encrypted so that they may be subsequently decrypted and used to verify the multi-spiral structure on a disc reading device.