Protection mechanism of the system. Please use the mobile terminal to open the page and sign it. When installing software in a smartphone, you need to sign it. This is the protection mechanism of the system. Software publishers should digitally sign their own software to ensure that the integrity of their software has not been implanted with other malicious programs. Users can also easily identify the real publisher of the software. Therefore, if developers want their software to be installed by more people, they need to apply for a mobile code signing certificate to digitally sign their software.