SERVER DEVICE AND INFORMATION TERMINAL FOR SHARING INFORMATION
First Claim
1. A server device comprising:
- a reception device for receiving encrypted change information which shows a change in information stored in a storage device of an information terminal device, the change being caused by a change operation on the stored information, the encrypted change information being encrypted so that the information terminal device can decrypt the encrypted change information; and
a storage device which stores the encrypted change information.
1 Assignment
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Accused Products
Abstract
A technique for synchronization of the information on multiple information terminal devices is disclosed. The information to be stored is stored in encrypted format in a server unit, and thus the server unit administrator cannot access this information. In the information terminal device where information is to be synchronized, encrypted changed information, where difference information or any set of difference information generated due to changes in the information, is encrypted, and is sent to the server unit. Then the server unit stores this encrypted changed information by correlating a revision number with it. A terminal device receives the revision number correlated with the encrypted changed information, and stores it by correlating it with the difference information or any set of difference information. The information is synchronized by maintaining consistency between information terminal devices, whose information is to be synchronized, by executing “Commit” and “Update” while exchanging the revision number correlated with the encrypted changed information, between the server unit and each information terminal device.
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Citations
27 Claims
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1. A server device comprising:
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a reception device for receiving encrypted change information which shows a change in information stored in a storage device of an information terminal device, the change being caused by a change operation on the stored information, the encrypted change information being encrypted so that the information terminal device can decrypt the encrypted change information; and a storage device which stores the encrypted change information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An information terminal device comprising:
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a key storage device which stores a decryption key; a reception device which receives encrypted information which can be decrypted by the decryption key, and revision information which shows an order in which the encrypted information is received by a server device; a decryption device which decrypts the received encryption information, and; a storage device which correlates the decrypted information with the received revision information. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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26. An information sharing system comprising a server and a plurality of information terminal devices,
each of the plurality of information devices including: - a storage device which stores information in plain format, an encryption device which encrypts change information which shows a change in information caused by a change operation on the stored information, the change information being encrypted so that the plurality of information terminal devices can decrypt the encrypted change information, a transmission device which transmits the encrypted change information to the server, a reception part which receives the encrypted change information transmitted from another information terminal device among the plurality of information terminal devices via the server device, a decryption device which decrypts the received encrypted change information, and an updating device which updates the stored information in plain format based on the decrypted encrypted change information; and
the server device including;
a reception device which receives encrypted change information transmitted from one of the plurality of information terminal devices, a storage device which stores the received encrypted change information, and a transmission device which transmits the encrypted change information to another of the plurality of information terminal devices other than the information terminal device which transmit the encrypted change information.
- a storage device which stores information in plain format, an encryption device which encrypts change information which shows a change in information caused by a change operation on the stored information, the change information being encrypted so that the plurality of information terminal devices can decrypt the encrypted change information, a transmission device which transmits the encrypted change information to the server, a reception part which receives the encrypted change information transmitted from another information terminal device among the plurality of information terminal devices via the server device, a decryption device which decrypts the received encrypted change information, and an updating device which updates the stored information in plain format based on the decrypted encrypted change information; and
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27. An information sharing method using a server and a plurality of information terminal devices, each of the plurality of information terminal devices storing information in the plain format, the information sharing method comprising:
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generating and transmitting by one of the plurality of information terminal devices change information which shows a change information caused by a change operation on stored information, the change information being encrypted so that each of the plurality of information terminal devices can decrypt the encrypted change information; receiving by another of the plurality of information terminal devices the encrypted change information transmitted by the information terminal device among the plurality of information terminal devices via the server; decrypting the received encrypted change information; updating by the another of the plurality of information terminal devices the stored information based on the decrypted encrypted change information; receiving the encrypted change information by the server; storing by the server the received encrypted change information, and; transmitting by the server the encrypted change information to the another information terminal device among the plurality of information terminal devices.
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Specification