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: 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 method and a device for managing a computer network, especially a technique for ensuring the security of a network. A computer network system in which computers are connected to each other through transmission lines, each computer stores the data which constitutes a moving type software exclusively used for security and transmitted together with a message when the computer transmits the message to another computer of the system, and executes the moving type software by using the stored data upon receiving a message from another computer.

Abstract: The digital signal recording/reproducing apparatus inputs a digital signal having a control flag as to a temporary copy permission, and records the digital signal temporarily into a recording medium in accordance with conditions in the control flag, then reproducing the digital signal temporarily from the recording medium in accordance with the conditions in the control flag. The recording/reproducing of the temporary copy is permitted, depending on the following conditions: The recording medium's type, the re-producing point-in-time, the reproducing time-period, and the reproducing frequency. With this method employed, even in a program permitting no recording, the temporary recording/reproducing is permitted under a condition of being limited to the time-shift recording on the receiving side.

Abstract: A method and a device for managing a computer network, especially a technique for ensuring the security of a network. A computer network system in which computers are connected to each other through transmission lines, each computer stores the data which constitutes a moving type software exclusively used for security and transmitted together with a message when the computer transmits the message to another computer of the system, and executes the moving type software by using the stored data upon receiving a message from another computer.

Abstract: According to the present invention, techniques, including a method and system, for restoring and/or validating data and/or associated signature log entries are provided. One embodiment of the present invention provides a method for validating a restored message, having an entry generated in a signature log for a message, where the entry includes cryptographic information associated with the message; Next, when said message is lost, the restored message is generated responsive to a request; and the restored message is validated using the signature log. In another embodiment a method for validating a selected log entry by using a signature log having a plurality of recorded log entries is provided. The method includes: computing a cryptographic value for the selected log entry; and determining if the cryptographic value is part of another recorded log entry.

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: The digital signal recording/reproducing apparatus inputs a digital signal having a control flag as to a temporary copy permission, and records the digital signal temporarily into a recording medium in accordance with conditions in the control flag, then reproducing the digital signal temporarily from the recording medium in accordance with the conditions in the control flag. The recording/reproducing of the temporary copy is permitted, depending on the following conditions: The recording medium's type, the reproducing point-in-time, the reproducing time-period, and the reproducing frequency. With this method employed, even in a program permitting no recording, the temporary recording/reproducing is permitted under a condition of being limited to the time-shift recording on the receiving side.

Abstract: A method of embedding digital watermark information b1–bn (2?n) in image data. The image data is divided into a plurality of areas S each consisting of M×N (1?M, N) pixels. A plurality of areas G each consisting of P×Q (1?P, Q) of the areas S are defined. Each of the areas S constituting each area G is allocated to some one of: areas T1–Tn in which said digital watermark information b1–bn is respectively embedded and areas H1–Hm (1?m) in which information is not embedded. One or more areas T and one or more areas H are located in a predetermined arrangement in each area G. And, the plurality of areas G are located in a predetermined rule.

Abstract: To lighten the processing load of embedding a digital watermark in content data, a preliminary process (embedding strength map generating process) run by a preprocessing section and the main process (digital watermark embedding process) run by a man processing section are run mutually independently. Specifically, the preliminary process of the preprocessing section is run each time new content data is stored to the content data database, and the main process of the main processing section is run when a content delivery request is received from a receiving terminal (client).

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: According to the present invention, techniques, including a method and system, for restoring and/or validating data and/or associated signature log entries are provided. One embodiment of the present invention provides a method for validating a restored message, having an entry generated in a signature log for a message, where the entry includes cryptographic information associated with the message. Next, when said message is lost, the restored message is generated responsive to a request; and the restored message is validated using the signature log. In another embodiment a method for validating a selected log entry by using a signature log having a plurality of recorded log entries is provided. The method includes: computing a cryptographic value for the selected log entry; and determining if the cryptographic value is part of another recorded log entry.

Abstract: An apparatus for restricting a copy of digital information is provided with a detecting device for detecting a first watermark, which is buried in the digital information and comprises a first signal generated on the basis of a first rule. A burying device buries a second watermark, which comprises a second signal generated on the basis of a second rule and having a structure different from that of the first signal, into the digital information if the first watermark is detected by the detecting device. A recording apparatus is provided with: an inputting device for inputting the digital information; the above mentioned copy restricting apparatus; and a recording device for recording the digital information in which the second watermark is buried by the burying device.

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 method and apparatus for embedding information into a target element in which information is to be embedded and a storage medium. The method and apparatus include obtaining plural sets of data values of a plurality of elements, wherein each set of data values is obtained along one direction extending through the target element, determining a strength of embedding information into the target element based on the plural sets of data values obtained, and embedding information into the target element based on the strength determined. The storage medium stores a program which enables embedding information by execution by a computer.

Abstract: An apparatus and method for embedding additional information embeds plural pieces of additional information on a signal as electronic watermark information. In detail, plural pieces of additional information to be embedded on a signal are generated, the additional information is converted into electronic watermark information, the sizes of embedding parts for respective electronic watermark information are defined under control, and the electronic watermark information is embedded on the signal based on the control signal. Therefore, the additional information are embedded so that additional information having a higher significance degree can be more reliably and rapidly detected.

Abstract: This invention provides a method for identifying a purchaser who purchased content from which an illegal copy was produced. A provider system encrypts a content 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 multimedia data distributing system comprising an ID issuing center side device and a multimedia data distributor side device for distributing multimedia data as electronic data to a purchaser of the multimedia data.

Abstract: A search service provided by an electronic data search system including a search center and at least one authorization center. The search center receives a search request from an information browsing apparatus and in response searches for URLs that are associated with a search condition included in the search request in a search database that registers URLs of Web pages, associating those URLs with respective search conditions. The search center presents the information browsing apparatus with link information to the detected URLs. When the search request also includes a condition that authorization by the authorization center be given, then URLs that are registered in the search database associated with the search condition, and registered in the authorization center are searched. Link information of detected URLs is presented to the information browsing apparatus and the authorization center registers URLs of Web pages opened by information disclosing persons who have been given authorization.

Abstract: To enable the control of rendering contents in part by using digital watermark technique: a contents serving center for embedding watermark in contents 4 embeds control information as digital watermarks within at least one of a plurality of blocks constituting electronic data by which contents are represented, thereby specifying the application of filtering to a part of the contents corresponding to the block; a contents distribution center 1 distributes the watermark-including contents to a receiving terminal 2 where checks the blocks of the received data to detect whether the control information as digital watermarks is embedded therein and applies the filtering to the block for which the embedded control information embedded has been detected in advance of reproducing the contents.