Secret grouping apparatus, secret grouping system, secret grouping method, and program
View Patent ↗A secret grouping apparatus which classifies a plurality of elements into one or more groups includes a processor configured to receive a target vector in which the plurality of elements are disposed so that elements belonging to a same group are continuous, a group information vector representing a last element in the group, and a classification destination vector representing a classification destination of each of the elements in the group; calculate a detection vector representing a last element of elements classified into a same classification destination in the group by using the target vector, the group information vector, and the classification destination vector; and stably sort the target vector and the detection vector with respect to the classification destination vector to create a target vector after classifying each of the elements into the classification destination and a group information vector representing a last element in a group after the classification.
1. A secret grouping apparatus which classifies a plurality of elements into one or more groups through secret calculation, comprising:
a memory; and
a processor coupled to the memory and configured to
receive, as an input, a target vector in which the plurality of elements are disposed so that elements belonging to a same group are continuous, a group information vector representing a last element in the group, and a classification destination vector representing a classification destination of each of the elements in the group;
calculate a detection vector representing a last element of elements classified into a same classification destination in the group by using the target vector, the group information vector, and the classification destination vector; and
stably sort the target vector and the detection vector with respect to the classification destination vector to create a target vector after classifying each of the elements into the classification destination in the group and a group information vector representing a last element in a group after the classification.
2. The secret grouping apparatus according to claim 1 , wherein the group information vector is a vector in which an element at a same position as a last element of elements belonging to the same group among elements constituting the target vector is 1 and an element other than the element at the same position as the last element is 0.
3. The secret grouping apparatus according to claim 1 , wherein the processor is further configured to
calculate, for each of values which are able to be taken as classification destinations, a classification destination unit detection vector representing a last element among elements classified into a classification destination corresponding to a value which is able to be taken in the group, and
calculate the detection vector by calculating a sum of classification destination unit detection vectors for all of the values which are able to be taken.
4. The secret grouping apparatus according to claim 3 , wherein the processor is further configured to
calculate a first vector representing a result of a comparison operation by performing the comparison operation between elements constituting the classification destination vector and the value which is able to be taken,
calculate a second vector by calculating a cumulative sum of elements constituting the first vector in order from a last element to a first element in the group,
calculate a third vector by calculating a product of the first vector and the second vector, and
calculate the classification destination unit detection vector by performing a comparison operation between each element constituting the third vector and 1.
5. A secret grouping system which classifies a plurality of elements into one or more groups through secret calculation, comprising:
a memory; and
a processor coupled to the memory and configured to
receive, as an input, a target vector in which the plurality of elements are disposed so that elements belonging to a same group are continuous, a group information vector representing a last element in the group, and a classification destination vector representing a classification destination of each of the elements in the group;
calculate a detection vector representing a last element of elements classified into a same classification destination in the group by using the target vector, the group information vector, and the classification destination vector; and
stably sort the target vector and the detection vector with respect to the classification destination vector to create a target vector after classifying each of the elements into the classification destination in the group and a group information vector representing a last element in a group after the classification.
6. A secret grouping method performed by a computer in which a plurality of elements are classified into one or more groups through secret calculation, the secret grouping method comprising:
receiving, as an input, a target vector in which the plurality of elements are disposed so that elements belonging to a same group are continuous, a group information vector representing a last element in the group, and a classification destination vector representing a classification destination of each of the elements in the group;
calculating a detection vector representing a last element of elements classified into a same classification destination in the group by using the target vector, the group information vector, and the classification destination vector; and
stably sorting the target vector and the detection vector with respect to the classification destination vector to create a target vector after classifying each of the elements into the classification destination in the group and a group information vector representing a last element in a group after the classification.
7. A non-transitory computer-readable recording medium storing a program causing a computer to function as the secret grouping apparatus according to claim 1 .