PROBLEM TO BE SOLVED: To determine proximity with other numerical information while keeping numerical information secret.;SOLUTION: A key generation server 2 distributes primary coupling of the row vector of a key matrix generated by adding random number vector as a final column to a matrix including a threshold for determining a vicinity range as a diagonal component to a terminal device 3 and an information providing device 4. The terminal device 3 transmits first secret vector to a vicinity determination server 7 based on first numerical information, a first random number, and the primary coupling of the key matrix. The information providing device 4 transmits second secret vector to the vicinity determination vector 7 based on second numerical information, a second random number, and the primary coupling of the key matrix. The vicinity determination server 7 calculates surplus vector which is a surplus when the key matrix is a normal from a difference between the first secret vector and the second secret vector, and determines whether the first numerical information and the second numerical information belong to the vicinity range based on the calculated surplus vector.;COPYRIGHT: (C)2014,JPO&INPIT
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