Patent ID: 11157612

Abstract:
To detect tampering in secure computation while maintaining confidentiality with a little communication traffic. A random number generation part (11) generates [{right arrow over ( )}ri], [{right arrow over ( )}si]. A random number multiplication part (12) computes [{right arrow over ( )}ti]:=[{right arrow over ( )}ri{right arrow over ( )}si]. A secret multiplication part (13) computes [{right arrow over ( )}z]:=[{right arrow over ( )}x{right arrow over ( )}y]. A random number verification part (14) discloses a pi,jth element of each of [{right arrow over ( )}ri], [{right arrow over ( )}si], [{right arrow over ( )}ti] and confirms whether the element has integrity as multiplication. A random number substitution part (15) randomly substitutes elements in each of [{right arrow over ( )}ri], [{right arrow over ( )}si], [{right arrow over ( )}ti] except for the pi,j-th element to generate [{right arrow over ( )}r′i], [{right arrow over ( )}s′i], [{right arrow over ( )}t′i]. A subtraction value disclosure part (16) computes [{right arrow over ( )}x−{right arrow over ( )}r′i], [{right arrow over ( )}x−{right arrow over ( )}s′i]. A verification value computing part (17) computes [{right arrow over ( )}ci]:=[{right arrow over ( )}z]−({right arrow over ( )}x−{right arrow over ( )}r′i)[{right arrow over ( )}y]−({right arrow over ( )}y−{right arrow over ( )}s′i)[{right arrow over ( )}r′i]−[{right arrow over ( )}t′i]. A verification value confirmation part (18) confirms that verification values ci are all zero.