SECRET COMPUTATION SYSTEM, ARITHMETIC UNIT, SECRET COMPUTATION METHOD AND PROGRAM

摘要

To perform secret computation under a lower probability of success in falsification than before. Each of at least three arithmetic units 2 1 ,...,2 N comprises: a random number generating part determining a shared value [r] obtained by performing secret sharing of a random number r; a randomization part using a shared value [a 0 ],...,[a M-1 ] obtained by performing secret sharing of a value a 0 ,...,a M-1 and a shared value [r] to generate a randomized shared value a 0 ,...,a M-1 with the shared value [a 0 ],...,[a M-1 ] and a shared value [a 0 r],...,[a M-1 r] as a pair; a secret computation part determining a concealed function value [F([a 0 ],...,[a M-1 ])] by executing a function F including at least one secret operation while including a randomized shared value f i which is an operation target and an operation result depending on the contents of secret operation into the checksum C:=f 0 ,...,f µ-1 ; and a correctness proving part verifying correctness of the function value [F([a 0 ],...,[a M-1 ])] on the basis of a shared value [Ø] obtained by multiplying a sum total of shared values [f i ] included in the checksum C by the shared value [r] and a shared value [È] which is a sum total of shared values [f i r] included in the checksum C.