SENDING MESSAGES BY OBLIVIOUS TRANSFER

摘要

A system includes a server connectable to a client, the server configured to allow the client to acquire a message of an index designated by the client among N messages held by the server where N is an integer of two or more. The server includes a classification unit configured to classify the N messages into M classified messages by contents of the messages; a message encryption unit configured to encrypt each of the M classified messages; a message provision unit configured to provide the M encrypted classified messages to the client; and a key sending unit configured to send the client, by oblivious transfer, a message key for decrypting the classified message corresponding to the message of the index designated by the client.

主权项

1. A computer readable storage medium having computer readable instructions stored thereon that, when executed by a computer, implement a method of allowing a client to acquire a message of an index designated by the client among N messages held by a server where N is an integer of two or more, the method comprising:
classifying, by the server, the N messages into M classified messages by contents of the messages; encrypting each of the M classified messages; providing the M encrypted classified messages to the client; and sending the client, by oblivious transfer, a message key for decrypting the classified message corresponding to the message of the index designated by the client; wherein the server provides the client with the M encrypted classified messages arranged in one or more of: ascending order of data size, and random order changed from the original arrangement order of the N messages.