Recording medium manufacturing device and method

Abstract

An information recording processing constitution realizing both readout difficulty and high-precision readout is provided. Superimposition recording of highly secret additional information such as a cryptographic key in a groove signal recorded on a disk, which superimposition recording realizes both readout difficulty and high-precision readout, can be performed. The groove signal to which a phase error corresponding to a bit value is set is recorded at a time of recording of the additional information, and at a time of readout of the additional information, the phase error of the groove signal in a predetermined section is subjected to an integrating process and the direction of the phase error of the groove signal within each section is determined. The recording and reproduction of the additional information for increasing readout difficulty and realizing high-precision readout is realized by such processes.

Dependencies are inferred from the claim text.