Confidential computing system, secret calculation method, secret calculation device and secret calculation program

摘要

The present invention executes secret multiplication in which the calculated value, the calculation result, and the value in the middle of the calculation can not be known while suppressing the overall communication amount. The secret calculation system is a distributed information generation device that generates a distributed data value, a distributed code value, and a distributed carry value obtained by distributing each fixed point number from at least two fixed point numbers using an additive type secret sharing method. The extended fixed data value is obtained by extending the number of digits using the distributed data value of each fixed-point number, the distributed code value, and the distributed carry value, and each distributed fixed including the extended distributed code value and the extended distributed carry value A secret digit expansion unit that generates a decimal number while holding a secret, and an extended dispersion data value and an extended dispersion code value of an extended multiplication result obtained by multiplying the distributed first extended fixed point number and the second extended fixed point number. At least two secrets including a secret multiplication unit that generates a spread distributed carry value while holding the secret, and adjusts the number of digits of the spread distributed data value of the extended multiplication result to be a dispersed value of the secret multiplication result It comprises a computing device.