An electric system including a first wireless apparatus, a display apparatus and a second wireless apparatus is provided. A first information is encrypted to be a first encrypted information and sent wirelessly by the first wireless apparatus. The display apparatus includes a display unit and a wireless communication unit electrically connected to the display unit. The wireless communication unit receives the first encrypted information and cause the display unit to display a first representative information corresponding to the first encrypted information. The first representative information and the first encrypted information are different. The second wireless apparatus reads the first encrypted information by the wireless communication unit, and the first encrypted information is decrypted to be the first encrypted information by the second wireless apparatus.