Patent ID: 7370070

Claim:
A data sharing method of sharing first data with a communication partner, comprising: a first obtaining step of obtaining second data from third data by using server-aided computation; a generation step of generating fourth data to be used by the communication partner for obtaining the first data, from the second data and fifth data; and a second obtaining step of obtaining the first data to be shared with the communication partner from sixth data generated from the third data and seventh data, wherein, in the first obtaining step, ninth data is obtained by using server-aided computation on the basis of eighth data obtained from the third data by first conversion, and the second data is generated from the ninth data by using second conversion corresponding to the first conversion, and in the second obtaining step, eleventh data is obtained by using server-aided computation on the basis of tenth data obtained from the sixth data by third conversion, and the first data is generated from the eleventh data by using fourth conversion corresponding to the third conversion.