Electronic data delivery method

An electronic data delivery method for delivering electronic data by using the secret sharing method, the method comprising steps of:

• dividing, by a transmission source device as a transmission source of the electronic data, the electronic data into a partial data group having a predetermined number of partial data by using the secret sharing method;
• classifying, by the transmission source device, the partial data group into a first partial data group and a second partial data group;
• creating, by the transmission source device, auxiliary data for restoring the electronic data from the partial data of the partial data group corresponding to the partial data of the first partial data group, the auxiliary data including positional relationship information associated with a storage position of the second partial data group;
• transmitting, by the transmission source device, the auxiliary data and the first partial data group to a transmission destination device as a transmission destination of the electronic data via a network, and the second partial data group to a data server via the network;
• receiving, by the transmission destination device, the first partial data group and the auxiliary data;
• specifying, by the transmission destination device, a storage position of the second partial data group by using the auxiliary data;
• accessing, by the transmission destination device, the specified storage position and reading the partial data of the second partial data group from the data server;
• and
• restoring, by the transmission destination device, the electronic data from the partial data of the second partial data group which has been read in and the partial data of the received first partial data group by using the auxiliary data.

An electronic data delivery system for delivering electronic data by using the secret sharing method;

• the system comprising:
• a transmission source device including:
• division means for dividing the electronic data into a predetermined number of partial data by using the secret sharing method;
• creation means for creating auxiliary data corresponding to the predetermined number of partial data and containing information indicating number information indicating a total number of the auxiliary data and the partial data;
• and transmission means for transmitting the partial data and the auxiliary data to the transmission destination device as a transmission destination of the electronic data via a network;
• and
• a transmission destination device including:
• reception means for receiving the partial data and the auxiliary data;
• storage means for storing reception data containing the partial data and the auxiliary data in the storage device;
• detection means for detecting presence/absence of tamper of the partial data and the auxiliary data by using the auxiliary data;
• and restoration means for restoring the electronic data from the partial data.