摘要:
A watermark information detection process prevents prolonging of time required for setup process when no watermark information can be detected from an optical disc where watermark information has been recorded. During a setup, the number of retrials is limited. Weighting of the retrial is changed so that detection of watermark information is performed when it is confirmed that watermark information is recorded. This enables detection of information for copyright protection in an appropriate processing time.
摘要:
A watermark information detection process prevents prolonging of time required for setup process when no watermark information can be detected from an optical disc where watermark information has been recorded. During a setup, the number of retrials is limited. Weighting of the retrial is changed so that detection of watermark information is performed when it is confirmed that watermark information is recorded. This enables detection of information for copyright protection in an appropriate processing time.
摘要:
A storage system having a plurality of optical disc devices allows other optical disc devices inside the storage system to reproduce the optical disc recorded by a certain optical disc device but inhibits optical disc devices outside the storage system to reproduce the optical disc. A device key as a base for generating an encryption key is common to the plurality of optical disc devices. In the optical disc devices, a guest key other than the device key can be used temporarily to generate the encryption key. An authentication list containing a reproduction condition is recorded with the key information to the optical disc.
摘要:
There is provided a method of calculating the degradation over time of the quality of data recorded on an optical disk in a short time. In the method, when user data is recorded on a data area, a test signal including a component in which the signal level is smaller than a reference value, is recorded on a test area. Then, the test signal is reproduced from the test area when a predetermined time has passed, to calculate the quality degradation of the user data from the evaluation result. Alternatively, every time when the user data is recorded/reproduced on/from the data area, the test signal is recorded/reproduced repeatedly on/from the test area. Then, the test signal is reproduced from the test area at a predetermined timing, to calculate the quality degradation of the user data from the evaluation result.
摘要:
An authentication method for use in sending/receiving data between a coded data output apparatus for outputting coded data having a water mark, and a recording apparatus for recording data onto a recording medium, the method including: deciding a type of the recording medium used by the recording apparatus; based on a result of the deciding, selecting, from a plurality of authentication methods, an authentication method corresponding to the type of the recording medium, and conducting authentication between the coded data output apparatus and the recording apparatus, using the authentication method; sending/receiving data between the coded data output apparatus and the recording apparatus after conducting the authentication; and in a case where the coded data has the water mark, detecting the water mark by the coded data output apparatus, wherein the data exchanged between the coded data output apparatus and the recording apparatus is scrambled by a scrambling method corresponding to the type the recording medium.
摘要:
To update the program, the file is updated by verifying according to a digital signature attached to the file having the program converted whether the file is not dishonestly falsified. To verify the digital signature, a time for verifying the signature can be shortened by verifying not the entire file but only a particularly important part, and an area for temporarily storing the file can be made small. Thus, the control can be performed to update only when the file is valid.
摘要:
A digital data recording/reproducing method includes the steps of: interleaving data on a PI code for each PI code of a 208-row ECC block; and converting a short burst error into random errors by dispersing errors on the PI codes. Moreover, the digital data recording/reproducing method increases correction capability against several bytes to several tens bytes of errors generated at random without changing burst error correction length by performing this processing for respective PI codes by using interleave rules that are different as much as possible from one another.
摘要:
A data reproducing method for a plurality of devices, for sending and receiving data by authenticating the plurality of devices with each other, said data reproducing method including: selecting, from a plurality of descrambling methods, a scrambling method corresponding to a type of said data, executing authentication by an authenticating method corresponding to the selected descrambling method, where the authenticating method is selected from a plurality of authenticating methods, and reproducing said data.
摘要:
A digital data recording/reproducing method includes the steps of: interleaving data on a PI code for each PI code of a 208-row ECC block; and converting a short burst error into random errors by dispersing errors on the PI codes. Moreover, the digital data recording/reproducing method increases correction capability against several bytes to several tens bytes of errors generated at random without changing burst error correction length by performing this processing for respective PI codes by using interleave rules that are different as much as possible from one another.
摘要:
If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations which can be performed is restricted.To solve the above problems, the present invention can record data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.