Patent ID: 8504830

Claim:
A transfer data management system for internet backup in which a backup server and a plurality of backup clients are connected via a network, and the backup server provides to the backup clients a function of backing up on the backup server data stored on the backup clients, as well as a function of restoring backed up data on the backup clients, wherein each of the backup clients comprises: a processor, memory device and a network interface; a digest information sending portion that sends to the backup server digest information of data to be backed up prior to a data backup request from the backup client to the backup server; a verification data receiving portion that receives, as verification data, stored data corresponding to the data to be backed up, which is sent from the backup server on the condition that the backup server has performed verification on the data to be backed up based on the digest information and the stored data on the backup server, an examining portion for examining whether or not the verification data and the data to be backed up match, wherein the backup server comprises: a processor, memory device and a network interface; a first encrypting portion that encrypts the verification data, and the backup server sends, to the backup client that sent the backup server digest information, the verification data and information regarding an encryption scheme thereof, wherein the backup client further comprises a second encrypting portion that encrypts the data to be backed up according to the received encryption scheme, wherein the examining portion determines whether or not the received verification data and the data to be backed up match, if the received verification data and the data to be backed up match, a backup request packet is transmitted to the backup server and the data to be backed up is temporarily stored on the backup client but not sent from the backup client, if the received verification data and the data to be stored do not match, the encrypted data to be backed up and the backup request packet are transmitted to the backup server from the backup client, and wherein, at the verification portion of the backup server, verification is performed independent of the backup clients and with respect to, as a whole, data of the plurality of the backup clients as the stored data.