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 method of communication involving processing by instruction using one or a combination of information units, when a user instructs a terminal to display contents and procedure of a communication, or to totalize the contents of the communication, or when a manager terminal instructs a field of the communication to provide a function of the communication corresponding to an object or stage of the communication. Information units forming the contents of the communication include cards, and information units forming premising information of a communication and a basis of the communication include boards. An information unit comprises a board identifier and attribute information for specifying a function of a board, such as a relationship between the board and cards. To provide a communication function corresponding to an object and stage of the communication, a template conforms to the object and stage so a manager can select and utilize the template.

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: 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 original signature can be verified even if a signed image data is properly altered in its portion. The digital image data is divided into a plurality of configurational elements, and each of the feature values of the elements are calculated, so that the signature is created by combining the feature values. In case the configurational elements are to be deleted, they are substituted by substitutive data, and only the feature values are stored. The verification is created by using the stored feature values as the substituted elements and by using the calculated feature values as the remaining elements, so that the signature is verified with the signature attached to the digital image data.

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 communication system includes a community management server used by a communication manager and a participant's terminal used by a community participant participating in communication. The community management server manages multimedia data that has data about the community participant embedded therein, an element symbolizing the community participant, a data content display control part and a participant personal identification authentication part. The participant's terminal includes generation part for generating card-like information as a communication unit. When a plurality of community participants executes communication by using the cards to which the multimedia data are put, they can execute information display of personal information of the community participants, authentication of personal identification, and retrieval/edition of a speech content by using information embedded in the multimedia data.

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 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 for communication making a processing by means of one of the information units or a combination of the information units when it is instructed from a user terminal to display contents and procedure of a communication or to totalize contents of the communication, or when it is instructed from a manager terminal of a field of the communication to provide a function of the communication corresponding to an object or stage of the communication, the processing corresponding to the instruction.

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: 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: 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 mark management server for certifying digital data based on a digital mark to enable realization of identity authentication and data certification when the digital data is transmitted or received on a network.

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 method of managing an electronic mark using an agent includes the steps of filing an application of issuing the electronic mark together with user information to be buried in the electronic mark, entrusting generation of the electronic mark together with the information of the user who applied for issuance of the electronic mark and the original image information for representing original image data where the user information is to be buried; generating the electronic mark by burying the information of the user in the original image data represented by the original image information to be generated; and providing the generated electronic mark to a mark user who filed an application of issuing the electronic mark.

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: Multimedia data having, embedded therein by using electronic watermark technique, data that includes first information to be disclosed, and second information for controlling the data to be disclosed is received by a data terminal via a communication network. The data terminal compares the second information included in the received multimedia data with the condition on the data terminal side. At least part of the multimedia data or first information is not displayed or is made illegible on the data terminal according to a result of the comparison of the second information. The multimedia data or the first information is displayed on the data terminal according to another result of the comparison of the second information.

Abstract: A communication system includes a communication management server used by a communication manager and a participant's terminal used by a community participant participating in communication. The community management server manages multimedia data that has data about the community participant embedded therein, an element symbolizing the community participant, a data content display control part and a participant personal identification authentication part. The participant's terminal includes generation part for generating card-like information as a communication unit. When a plurality of community participants executes communication by using the cards to which the multimedia data are put, they can execute information display of personal information of the community participants, authentication of personal identification, and retrieval/edition of a speech content by using information embedded in the multimedia data.