| 摘要 |
Distributed values of concealed secret information are obtained from secret information by concealing the secret information. A combined value α is generated from random numbers α1 to αk, which are k or more items of secret information (42). The combined value α is multiplied by new secret information a to generate concealed secret information αa, and distributed values Wa'(xi) of the concealed secret information, and distributed values Wa1(xi) to Wak(xi) of each of the random numbers, which are the k or more items of secret information, are calculated (44). The distributed values Wa'(xi) and Wa1(xi) to Wak(xi) are transmitted to first to nth servers (46). The distributed values Wa'(xi) of the concealed secret information αa, obtained by concealing the secret information α1 to αk, can be obtained from the secret information α1 to αk. |
