Patent ID: 11937078
Assignee: CRYPTO LAB INC.
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 9:
10. The non-transitory recording medium according to claim 9, wherein the generating the movement path information comprises:
calculating a vector value by encoding the plurality of pieces of location information to each element in a plaintext space of a homomorphic ciphertext; and
performing homomorphic encryption on the calculated vector value to generate the movement path information,
the operation result data is ctxt:=(Enc({right arrow over (a)})−{right arrow over (b)})⊙{right arrow over (r)},
wherein, {right arrow over (r)} represents a random vector, {right arrow over (b)} represents the vector value obtained by encoding the comparison target path information, and Enc({right arrow over (a)}) represents the movement path information subjected to the homomorphic encryption, and
the outputting the message comprises:
based on an i-th element of the {right arrow over (ptxt)} obtained by decrypting the ctxt being 0, detecting that the route overlaps at a point where the mobile device is located at time ti, and based on all elements being not 0, detecting that the route does not overlap; and
generating and outputting a message corresponding to a detection result.