Abstract: A system for preventing unauthorized use of digital content that can prevent unauthorized use of digital content and can reliably collect a charge for secondary use is provided. The system for preventing unauthorized use may include: a distributing recording medium ? on which a content file having header information “A” and a data body “B” is recorded in a state of lacking play information “A1” indispensable for playing the data body “B” included in the header information a; a management center managing use of the content file on the distributing recording medium ? and which can deliver the prepared play information “A1” of the header information “A” as piece data via a communication line ?; and a digital content playing device which is a device used for playing the content file on the distributing recording medium ? and has a function of communicating via the communication line ? with the management center.

Abstract: An object of the present invention is to prevent illegal use of data (digital contents), and a second object is to provide a method for processing data which ensures the collection of charges for secondary use of the data, a data reading method for reading the data processed by this processing method, and a recording medium storing programs implementing these methods. The method for processing data is such that in a method for processing a data body b which is encrypted and is decrypted on a decryption bit length basis, and thereby is reproduced, the data body b is encrypted, a part of this data body b with a bit length different from the decryption bit length is omitted, and the omitted part is closed so as to make the data continuous.

Abstract: An object of the present invention is to prevent illegal use of data (digital contents), and a second object is to provide a method for processing data which ensures the collection of charges for secondary use of the data, a data reading method for reading the data processed by this processing method, and a recording medium storing programs implementing these methods. The method for processing data is such that in a method for processing a data body b which is encrypted and is decrypted on a decryption bit length basis, and thereby is reproduced, the data body b is encrypted, a part of this data body b with a bit length different from the decryption bit length is omitted, and the omitted part is closed so as to make the data continuous.

Abstract: An object of the present invention is to provide a system for preventing unauthorized use of digital content which can prevent unauthorized use of digital content and can reliably collect a charge for secondary use. Basically, a system for preventing unauthorized use of digital content has: a distributing recording medium ? on which a content file having header information “A” and a data body “B” is recorded in a state of lacking play information “A1” indispensable for playing the data body “B” included in the header information a; a management center 110 which is management means managing use of the content file on the distributing recording medium ? and can deliver the prepared play information “A1” of the header information “A” as piece data via a communication line ?; and a digital content playing device 120 which is a device used for playing the content file on the distributing recording medium ? and has a function of communicating via the communication line ? with the management center 110.

Abstract: [Problem to be solved] To rent a digital contents such as a movie or the like easily without a case in which the digital contents cannot be rented as it was rented by someone else.

Abstract: Hereby established is a method of disinfection by ozone which is safe, clean, more reliable, and more efficient than prior methods. The method comprises a step of calculating the amount of ozone which would be required to solely disinfect bacteria if there were no co-existing materials, a step of calculating the amount of ozone which will be consumed by actual co-existing materials and a step of applying the total value of the two ozone amounts in proper forms, such as, gas or liquid, etc., preferably in the form of aqueous solution, to the object to be disinfected. This method can be consistently adopted for disinfection on very wide varieties of bacteria.