Patent ID: 11005645

Abstract:
A data partition unit partitions character string data D into N pieces of element data w1, w2, . . . , wN from a front to an end of the character string data D. A partial character string generation unit generates a set A={A1, A2, . . . , AN} and an element Ai={(wi), (wiwi+1), . . . , (wiwi+1 . . . wN)} of the set A where i=1, . . . , N, from the element data w1, w2, . . . , wN. A position information assignment unit generates a set B={B1, B2, . . . , BN} and an element Bi={(i, wi, (i, wiwi+1), . . . , (i, wiwi+1 . . . wN)} of the set B by associating each of (wi), (wiwi+1), . . . , (wiwi+1 . . . wN) which are components of the element Ai with position information i. An encryption unit encrypts each of (i, wi), (i, wiwi+1), . . . , (i, wiwi+1 . . . wN) which are components included in the element Bi.