| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a means to recognize individual information from the information that is added to a recording medium by an optical means and to provide a method to protect against an unauthorized use of the data information of a recording medium using the individual information. SOLUTION: An optical disk head 2, which is used for record writing and reading, and a picture reading head 3, which is provided with an optical picture reading element 3a and a light source 3b, are arranged. The element 3a is used to read individual information, which is characters and symbols printed on a recording medium 1. Thus, even recorded information is same for the media, printed information individualizes the media. By relating the individual information and the recorded information, the reading of the recorded information, which is not related to the individual information is limited so as to prevent an unauthorized use of the medium. Moreover, by including a key in the individual information, ciphering and deciphering of recorded data are easily done and the recorded information is protected. |
