An information recording medium, such as an optical disk or the like, is provided for recording at least copyrighted content information and cipher key information. A part of the content information is scrambled and recorded in the information recording medium, and the scrambled and recorded part of the content information is obtained through scrambling using scramble key information, which is obtained by converting the cipher key information by the use of a non-scrambled part of the content information. The information recording medium has a recording area divided into a plurality of sectors. A plurality of data which the content information is divided into is recorded in the sectors. The non-scrambled part of the content information includes copy control information and a part of the content information that changes sector by sector.