US 12,475,237 B2
Secure computation apparatus, secure computation system, secure computation method, and program
Hiroki Sudo, Musashino (JP); and Dai Ikarashi, Musashino (JP)
Assigned to NTT, Inc., Tokyo (JP)
Appl. No. 18/566,678
Filed by NTT, Inc., Tokyo (JP)
PCT Filed Jun. 8, 2021, PCT No. PCT/JP2021/021741
§ 371(c)(1), (2) Date Dec. 4, 2023,
PCT Pub. No. WO2022/259366, PCT Pub. Date Dec. 15, 2022.
Prior Publication US 2024/0273219 A1, Aug. 15, 2024
Int. Cl. G06F 21/60 (2013.01)
CPC G06F 21/602 (2013.01) 6 Claims
OG exemplary drawing
 
1. A secure computation device that obtains a concealed operation result representing concealed information of a product set of L sets X0, . . . , XL-1 while concealing sets X0={x0,0, . . . , X0,r(0)-1}, . . . , XL-1={XL-1,0, . . . , XL-1,r (L-1)-1}, L being an integer of 2 or greater, i=0, . . . , L−1, r(i) being an integer of 1 or greater, j(i)=0, . . . , r(i)-1, m being an integer of 1 or greater, k0, . . . , km-1 being pieces of key information different from each other, p=0, . . . , m−1, and [α] being concealed information of α, the secure computation device comprising processing circuitry configured to:
(A) obtain count results [c0], . . . , [cm-1] through secure computation by using concealed elements [x0,0], . . . , [X0,r(0)-1], . . . , [XL-1,0], . . . , [XL-1,r(L-1)-1] where each element xi,j(i) represents any one of the key information k0, . . . , km-1, and a number of elements representing key information kp among elements X0,0, . . . , X0,r(0)-1, . . . , XL-1,0, . . . , XL-1,r(L-1)-1 iS Cp;
(B) obtain equality check results [eq0], . . . , [eqm-1] through the secure computation by using count results [c0], . . . , [Cm-1], where eqp=T when cp is L, eqp=F when cp is not L, and T and F are different from each other; and
(C) output the concealed operation result including concealed key information [kp] and a equality check result [eqp] associated with each other,
wherein the processing circuitry is configured to further obtain concealed key information [k0], . . . , [km-1] through the secure computation by using the concealed elements [x0,0], . . . , [X0,r(0)-1], . . . , [XL-1,0], . . . , [XL-1,r(L-1)-1].