Abstract: Data protection techniques for preventing deletion, alteration, and leakage of data due to carelessness of a user and other programs (including a computer virus) and for preventing alteration of a program that uses the data are provided using a multi-OS control program, a host OS directly used by the user and a guest OS for managing files to be protected are run. A communication control program determines whether access from a signature request program can be performed or not, based on an access control list. In the case of access being authorized, a signature generation program is executed. The signature generation program generates a signature using a private-key. The communication control program sends back the generated signature to a requesting source through an inter-OS communication program.

Abstract: A digital watermark information is extracted from geometrically deformed image without using a calibrating digital watermark. Pixel data at positions predetermined in an X-Y coordinate used when embedding the watermark is extracted from image data in which the digital watermark has been embedded for given pixel data and compared with a reference value to determine whether the watermark has been embedded in the pixel data concerned or not. This processing is repeated until it is confirmed that the information is embedded in the pixel data concerned, while applying geometric deformation to the image data.

Abstract: A time stamp generating system has a time distribution server for generating time data depending on time and a user PC for holding time certification objective digital data. The time distribution server generates time data corresponding to a time point and distributes the time data. The user PC calculates time stamp generating data by using the time certification objective data as an input, acquires the time data generated by the time distribution server, and processes the time data on the basis of the time stamp generating data to obtain a time stamp.

Abstract: A reproducing apparatus for reproducing data from a recording medium and supplying the data to an external apparatus for recording of the data. The reproducing apparatus has a plurality of authenticators for authenticating the external apparatus and the reproducing apparatus selects an authenticator corresponding to a type of the data reproduced from the recording medium and conducts authentication with the external apparatus. After authentication is confirmed, the reproducing apparatus sends the data to the external apparatus to record the data by the external apparatus.

Abstract: An image processing apparatus having an adding unit to add information by changing a data value of image data and a detecting unit to detect the information added to the image data. In a digital watermark image processing method in the image processing apparatus, filter passage image data is formed by performing an image filtering process to original image data, watermark core image data is formed by performing a process to obtain a difference between the filter passage image data and the original image data, change amount image data is formed by performing a process to obtain a value to change the data value of the image data on the basis of the watermark core image data and desired information to be added, and watermark inserted image data is formed by performing a process to add the original image data and the change amount image data.

Abstract: In order to reproduce data scrambled in respective manners to recordable recording medium, it is necessary to take the step of discriminating if the reproduction signal comes from any recording medium before descrambling the data. Further, before doing the control, it is necessary to discriminate if the data is copy-permitted or copy-prohibited. To accomplish this process, a data recording and reproducing apparatus includes a first reproducing unit, a second reproducing unit for receiving the data processed by the first reproducing unit and executing the next reproducing process about the data, a first authenticating unit for authenticating the first reproducing unit, a second authenticating unit positioned in correspondence with the first authenticating unit and for authenticating the second reproducing unit.

Abstract: According to a digital watermark information extracting method, pixel data located at predetermined positions on X-Y coordinate used when digital watermark information is embedded are extracted from image data, and the data value of the pixel data is compared with a reference value to judge whether the watermark information is embedded in the pixel data concerned. This processing is repetitively executed while a geometrical deformation is applied to the image data until it is confirmed that the information is embedded in the pixel data.

Abstract: A system that can reduce possibility of outflow of private information in authentication of a user of an information terminal. A management apparatus has a user certificate DB in which a user certificate is registered in association with certificate identification information. Further, the management apparatus reads the user certificate associated with the certificate identification information sent from a service providing apparatus, from the user certificate DB, and judges whether the user certificate satisfies certain Web browsing conditions, to determine approval or denial of browsing the Web page concerned. Then, the management apparatus sends the service providing apparatus approval or denial information indicating the determination result.

Abstract: At recording of a video signal, with electronic watermark information being embedded therein, on a recording medium, a reference signal which is formed differently from the watermark information is inserted to the video signal. At reproduction of the video signal, the luminance of the watermark information is modified based on the reference signal.

Abstract: When a video signal having electronic watermark information embedded therein is recorded on a recording medium, a reference signal is inserted in the video signal at a position different from a position of embedment of the electronic watermark information. The electronic watermark information is embedded in the video signal by alteration of a luminous value of a luminance signal included in the video signal. When the video signal is reproduced from the recording medium, a luminous value of the electronic watermark information is modified based on the reference signal.

Abstract: A digital watermark information is extracted from geometrically deformed image without using a calibrating digital watermark. Pixel data at positions predetermined in an X-Y coordinate used when embedding the watermark is extracted from image data in which the digital watermark has been embedded for given pixel data and compared with a reference value to determine whether the watermark has been embedded in the pixel data concerned or not. This processing is repeated until it is confirmed that the information is embedded in the pixel data concerned, while applying geometric deformation to the image data.

Abstract: Techniques are provided which can prevent secret data or falsified data in a data providing system from being presented to a data requesting system. A data verifying system is installed in a network interconnecting the data requesting system and data providing system. The data verifying system checks whether verification data for supplied data matches the supplied data. In accordance with this check, data to be transmitted from the data verifying system to the data requesting system is altered.

Abstract: In the process of compressing and encrypting data, without an increase of processing time, a cipher capability is secured against the latest cryptanalysis such as differential and linear cryptanalyses. The differential and linear cryptanalyses are executed to collect plural pairs of plaintext and cryptosystem for the same key and perform the statistical operation for estimating the key. An input/output (I/O) process is executed to receive plaintext data and generate a different key for each data on the random number and set the key to a work key. The encrypted intermediate result or the pre-encrypted result is fed back to permit frequent changing of the work key. The changing operation is executed to change correspondence between the plaintext data and the compressed data in the compressing process.

Abstract: This invention provides a method for identifying a purchaser who purchased content from which an illegal copy was produced. A provider system encrypts purchased by the purchaser using a public key of a purchaser system and sends the encrypted content to the purchaser system. The purchaser system creates a digital signature of the content with the use of a private key of its own and embeds the created digital signature into the received content. When an illegal copy is found, the provider system verifies the digital signature, embedded in the illegal copy as a digital watermark, to identify the purchaser who purchased the content from which the illegal copy was produced.

Abstract: A digital watermark information detection method for detecting information inserted as a digital watermark from contents has a step of converting the contents into a predetermined specified format and a step of trying to detect information from the converted contents. When a plurality of specified formats are defined in advance and detection of the information from the converted contents fails, the contents is converted into another specified format and the information detection is retried.

Abstract: A contents control method for controlling a process on the receiving side which is applied to contents transmitted from the transmitting side to the receiving side, includes a step of adding, when a predetermined block of the transmitted contents is an area where control information for controlling the process substance on the receiving side which is applied to the contents is added, the control information to the block. The method also includes a step of receiving a process designation concerning the transmitted contents, and a step of applying, when user information stored in a receiving side apparatus which receives the transmitted contents, or information concerning the receiving side apparatus satisfies conditions corresponding to the received process designation in the control information added to the block of the contents, a process corresponding to the process designation to the received block.

Abstract: Techniques of improving the safety of an information processing system at low cost are provided, the information processing system having an OS provided with an access control function based upon discretionary access control for preventing illegal accesses to files. A method and apparatus for providing the information processing system with functions and areas usable only by a specific user different from a system administrator. The areas are provided with an access control function in order to prevent the access control function from being tampered.

Abstract: When a video signal having electronic watermark information embedded therein is recorded on a recording medium, a reference signal is inserted in the video signal at a position different from a position of embedment of the electronic watermark information. The electronic watermark information is embedded in the video signal by alteration of a luminous value of a luminance signal included in the video signal. When the video signal is reproduced from the recording medium, a luminous value of the electronic watermark information is modified based on the reference signal.

Abstract: A digital watermark information is extracted from geometrically deformed image without using a calibrating digital watermark. Pixel data at positions predetermined in an X-Y coordinate used when embedding the watermark is extracted from image data in which the digital watermark has been embedded for given pixel data and compared with a reference value to determine whether the watermark has been embedded in the pixel data concerned or not. This processing is repeated until it is confirmed that the information is embedded in the pixel data concerned, while applying geometric deformation to the image data.

Abstract: A system and method for realizing a tamper-resistant system which can prevent software running on a personal computer from being analyzed or altered illegally in a static or dynamic manner by a potential transgressor. Two operating systems, an OS1 controllable by a user and an OS2 operable in background, are concurrently run on a personal computer. Player software is run on the OS2 to protect the player software against illegal analysis and alteration by the user. Further, a hardware module, a system startup, and a key management operation are implemented. Still further, OS1 cannot direct access OS2, whereas indirect access of OS2 by OS1 is allowed in a manner whereby OS2 refers to an OS2 reference region in a memory area managed by OS1.