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

Claim 0:
1. A mobile device comprising:
a communicator;
a global positioning system (GPS) unit for calculating location information of the mobile device;
a memory;
a display; and
a processor configured to obtain a plurality of pieces of location information according to a location change of the mobile device from the GPS unit and store the plurality of pieces of location information in the memory,
wherein the processor is further configured to:
generate movement path information of the mobile device by performing homomorphic encryption of the plurality of pieces of location information stored in the memory, and transmit the movement path information to a server apparatus through the communicator;
based on operation result data obtained by operating based on the movement path information and comparison target path information being transmitted from the server apparatus, decrypt the operation result data;
output a message notifying whether a route overlaps the comparison target path information based on a decrypted result through the display; and
wherein the processor is further configured to encode the plurality of pieces of location information stored in the memory to each element in a plaintext space of a homomorphic ciphertext, calculate a polynomial configured with each encoded element, and perform homomorphic encryption on the calculated polynomial fA(x) to generate the movement path information,
the polynomial, f
      A
     
     (
     x
     )
    
    ⁢
       
    is
    ⁢
       
    
     
      f
      A
     
     (
     x
     )
    
   
   =
   
    
     
      
       ∏
        
      
      
        
       
        i
        =
        1
       
      
      
        
       n
      
     
     ⁢
     
      (
      
       x
       -
       
        a
        
         i
          
        
       
      
      )
     
    
    ∈
    
     
      Z
      p
     
     [
     x
     ]
    
   
  
  ,, and
wherein, x represents a variable, Zp[x] represents the plaintext space, and ai represents an i-th element in the plaintext space.