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

Claim 7:
8. The route overlap detecting method according to claim 5, wherein the operation result data is Enc(rA(x)·fA(x)+rB(x)·fB(x)),
wherein, rA(x) and rB(x) represent random polynomials, and fB(x) represents a polynomial obtained by encoding the comparison target path information, and
the outputting the message comprises:
calculating a greatest common denominator of g(x)=rA(x)·fA(x)+rB(x)·fB(x) obtained by decrypting the operation result data and the fA(x);
based on the greatest common denominator being, ∏
    
      
     
      i
      =
      1
     
    
    
      
     n
    
   
   
    (
    
     x
     -
     
      b
      i
     
    
    )
   
  
  ,, detecting that the route overlaps at a point where the mobile device is located at time ti that bi is decrypted, and based on the greatest common denominator being 1, detecting that the route does not overlap; and
generating and outputting a message corresponding to a detection result.