8. The method of claim 1 , wherein the tenth byte stores in the first four bits information relating to the sequential identification number and in the second four bits the four most significant bits of a second height coordinate with respect to a second height reference of the point where the two-dimensional code is located, and the eleventh byte comprises the eight least significant bits of the second height coordinate of the point where the two-dimensional code is located.
8. The method of claim 1 , wherein the tenth byte stores in the first four bits information relating to the sequential identification number and in the second four bits the four most significant bits of a second height coordinate with respect to a second height reference of the point where the two-dimensional code is located, and the eleventh byte comprises the eight least significant bits of the second height coordinate of the point where the two-dimensional code is located. 10. The method of claim 8 , wherein the unique key additionally comprises the information of the second height coordinate of the point where the two-dimensional code is located.