Reproducing apparatus and reproducing method

A reproducing apparatus for reproducing a file from a record medium on which a main file and a reproduction management file are recorded, the main file having an attribute header for managing forging prohibition information, the reproduction management file being used for managing at least clock information, the apparatus comprising:

• calculating means for calculating the forging prohibition information managed in a management area of the record medium using a predetermined function whenever the main file recorded on the record medium is reproduced and for calculating the clock information using the predetermined function whenever the clock information is updated;
• first comparing means for comparing a value calculated by said calculating means corresponding to a former reproduction command with that corresponding to a current reproduction command;
• second comparing means for comparing a value calculated by said calculating means corresponding to former clock information with a value calculated by said calculating means corresponding to current clock information;
• and
• controlling means for permitting the main file to be reproduced when the value calculated corresponding to the former reproduction command is the same as that corresponding to the current reproduction command as the result of said first comparing means or when the value calculated corresponding to the former clock information is the same s that corresponding to the current clock information as the result of said second comparing means.

A reproducing method for reproducing data from a record medium having a program area and a management area, the program area being used for recording a plurality of files, the management area being used for managing forging prohibition information against a particular file recorded in the program area, the method comprising the steps of:

• (a) calculating means for calculating the forging prohibition information managed in the management area of the record medium whenever a file recorded in the recorde medium is reproduced;
• (b) comparing means for comparing a value calculated at step (b) corresponding to a former reproduction command with a value calculated at step (b) corresponding to a current reproduction command;
• and
• (c) controlling means for permitting the file corresponding to the current reproduction command to be reproduced when the value calculated corresponding to the former reproduction command is the same as the value calculated corresponding to the current reproduction command as the result obtained at step (b).

A reproducing method for reproducing a file from a record medium on which a main file and a reproduction management file are recorded, the main file having an attribute header for managing forging prohibition information, the reproduction management file being used for managing at least clock information, the method comprising the steps of:

• (a) calculating means for calculating the forging prohibition information managed in a management area of the record medium using a predetermined function whenever the main file recorded on the record medium is reproduced and for calculating the clock information using the predetermined function whenever the clock information is updated;
• (b) first comparing means for comparing a value calculated at step (b) corresponding to a former reproduction command with that corresponding to a current reproduction command;
• (c) second comparing means for comparing a value calculated at step (a) corresponding to former clock information with a value calculated at step (a) corresponding to current clock information;
• and
• (d) controlling means for permitting the main file to be reproduced when the value calculated corresponding to the former reproduction command is the same as that corresponding to the current reproduction command as the result obtained at step (b) or when the value calculated corresponding to the former clock information is the same s that corresponding to the current clock information as the result obtained at step (c).