Data transmission device, data sharing system, data sharing method and message exchange system

摘要

A data transferring device that transfers data to another node includes: a data storage device for storing data; summary information storage means for classifying data stored in the data storage means into predetermined groups and for storing summary information representing the number of data items for each group; receiving means for receiving summary information from the other node; selecting means for selecting data to be transmitted based on the summary information received from the other node; and transmission means for transmitting the data selected by the selecting means. Advantageously, the selection means preferably selects data contained in a group with a smaller number of data elements based on the summary information received from the other node. Due to such a configuration, information that is highly likely not owned by a communication partner can be selected and transmitted in a data sharing system.