SECRET AGGREGATION RANK SYSTEM, SECURE COMPUTING DEVICE, SECRET AGGREGATION RANK METHOD, AND PROGRAM

摘要

The present invention efficiently obtains an aggregation rank while maintaining secrecy. An inverse substitution unit (12) applies, to the cross tabulation of a table, the inverse substitution of a substitution that moves so that, when the table is classified into groups on the basis of a key attribute, the last element of each group is aligned in order from the beginning and generates a vector share that represents an inverse-substituted cross tabulation. A partial sum total unit (13) calculates a prefix sum from the inverse-substituted cross tabulation. A rank calculation unit (14) generates a vector share from the result of the prefix sum that represents a rank in ascending order within a group.