Abstract: A software distribution system and a software utilization scheme for effectively preventing an illegal copy of a software is difficult while improving a convenience of a user. At a user side, a shared key to be shared between a software provider and a user is stored, where the shared key has a guaranteed correspondence with an ID information regarding a payment of a software fee by the user. Then, a desired software is requested to the software provider, and the desired software is received in an encrypted form from the software provider. The desired software received from the software provider is then decrypted by using the shared key stored at the user side, and the desired software in a decrypted form is utilized at the user side.

Abstract: A software distribution system and a software utilization scheme for effectively preventing an illegal copy of a software is difficult while improving a convenience of a user. At a user side, a shared key to be shared between a software provider and a user is stored, where the shared key has a guaranteed correspondence with an ID information regarding a payment of a software fee by the user. Then, a desired software is requested to the software provider, and the desired software is received in an encrypted form from the software provider. The desired software received from the software provider is then decrypted by using the shared key stored at the user side, and the desired software in a decrypted form is utilized at the user side.

Abstract: A software distribution system and a software utilization scheme for effectively preventing an illegal copy or a software is difficult while improving a convenience of a user. At a user side, a shared key to be shared between a software provider and a user is stored, where the shared key has a guaranteed correspondence with an ID information regarding a payment of a software fee by the user. Then, a desired software is requested to the software provider, and the desired software is received in an encrypted form from the software provider. The desired software received from the software provider is then decrypted by using the shared key stored at the user side, and the desired software in a decrypted form is utilized at the user side.

Abstract: A program execution and operation right management system capable of providing flexible and sufficient protection uniformly even for the thread operation instructions among the threads sharing the same virtual address space and/or for individual memory region. In the system, operation right data indicating which thread can be operated by which thread among a plurality of threads are stored, and whether a thread operation with respect to one thread requested by another thread among a plurality of threads is allowed by the operation right data is judged. Then, the processor is allowed to carry out said thread operation with respect to that one thread by that another thread only when it is judged that said thread operation is allowed by the operation right data.

Abstract: A file editing system that provides a high file content secrecy, a file version management, and an asynchronous editing is disclosed. For a high file content secrecy, the block data of files managed by a file management server device are enciphered in units of blocks, and a client device obtains the block data of the desired file in enciphered state, deciphers the obtained block data in units of blocks, carries out an editing of the desired file to obtain editing data, enciphers the editing data in units of blocks, and transmits the enciphered editing data to the file management server device.

Abstract: An object traversing scheme in which the traverse procedure and the traverse rights can be specified flexibly. In this scheme, the object is stored with an assignment of a traverse right for each sub-object indicating who is allowed to traverse each sub-object; at least one traverse IDs for identifying a user making a request to make an access to the object are specified; the sub-objects to be traversed at a time of traversing the object in response to the request from the user identified by the traverse IDs are selected according to the traverse right assigned to the user identified by the traverse IDs in the object; and the selected sub-objects are outputted as a result of the access to the object. The traverse IDs for identifying the user can be changed according to the traverse rights of the sub-objects and the selection of the sub-objects. This scheme can be utilized very beneficially in conjunction with an electronic mail tool.