A method for authenticating a digital optical medium to determine if it is original or an unauthorized copy. One or more special bistable data subunits are written onto the original digital optical medium by recording bistable data symbols and other intentional errors into the data subunit such that the data subunit will be on the error-correction limit threshold. A bistable data symbol is a data symbol for which a player will randomly read at least two different values. Depending on which values are read for the bistable data symbols, the bistable data subunit will either be error-free and readable (at or below the error-correction limit) or will be erroneous or unreadable (above the error-correction limit). When an unauthorized copy of the digital optical medium is made, the data subunit with the address of the bistable data subunit on the original digital optical medium will be a monostable data subunit with constant data, because special hardware equipment is needed to record bistable data symbols. Thus, by testing the stability of the appropriate data subunits, the undetermined digital optical medium can be authenticated as either original or an unauthorized copy. Methods for writing a bistable data subunit include replacing one or more data symbols in the data subunit with bistable data symbols and zero or more data symbols in the data subunit with erroneous data symbols. Methods for testing the stability of a data subunit include multiple readings and checking for error as well as measuring the time for a successful read using a player with a multiple retry capability.
A recording-medium management system comprising: a reproduction part; a recording part; and a control part. The control part performs a first through fourth control. The first control is to obtain a first data line from an authentication region of a recording medium by making the reproduction part read the authentication region, the authentication region including a first data pattern of a RAM bit and a ROM bit, the first data line being corresponding to the first data pattern, the RAM bit being over-writable of data at least once by a first writing condition, and the ROM bit being not over-writable of data by the first writing condition. The second control is to make the recording part overwrite predetermined data to the RAM bit. The third control is to obtain a second data line from the recording-medium, the second data line being corresponding to a second data pattern of the over-written RAM bit and the ROM bit. The fourth control is to perform an authentication with regard to the recording medium in reference to the first and second data lines.
One aspect of the invention includes one or more security devices embedded on one of the two surfaces, or between the two surfaces, of a compact disc (CD) or digital video disc (DVD) to impede the counterfeiting of the disc. The security devices may be, for example, holograms, optically variable devices (OVD) or RFID chips. CD/DVD is an authorized (non-pirated) version of a manufacturer's product. A system embodying the invention includes a player/reader which contains means for sensing selected characteristics of the security devices embedded on or within a CD/DVD and which is programmed to ascertain that the CD/DVD is in fact a valid document. Another aspect of the invention may include encrypting apparatus for reading/sensing selected characteristics of security device(s) and for annotating the disc and/or the security device(s) with corresponding information. Still another aspect includes a player/reader which is programmed to sense selected characteristics of security device(s) and/or to read information written back onto the disc and/or on the security device and to compare the information to ascertain the validity of the disc.
A signal processing method multiplexes/arranges digital data of a specific unit to form a predetermined unit, adds an error correction code to the predetermined unit to constitute an error correction coded block, replaces a part of the error correction coded block with specific data, and outputs the error correction coded block with the specific data being replaced to a transmission medium or a recording medium.
A signal processing method multiplexes/arranges digital data of a specific unit to form a predetermined unit, adds an error correction code to the predetermined unit to constitute an error correction coded block, replaces a part of the error correction coded block with specific data, and outputs the error correction coded block with the specific data being replaced to a transmission medium or a recording medium.
Theft, distribution, and piracy of digital content on optical media (software, video, audio, e-books, any content of any kind that is digitally stored and distributed) is often accomplished by copying it directly to another disc using commonly available copy tools and recordable optical media, or the copying of media to another mass manufactured disc. Methods which cause the copy process to become lengthy and inconvenient, or which produce copies that are significantly measurably different from the original and therefore be recognizable as copies, deter or prevent an unauthorized individual from making copies. This is accomplished by modifying the optical path of an optical medium to include regions of selective distortion. This, in turn, modifies the read operation of the data in the regions, which can be used to identify and authenticate the medium.
