Certificates are used to sign software. The third edition of the mobile phone adds a security mechanism to the software installation, that is, many softwares can only be installed normally after being signed, and the serial number of your mobile phone must be used as a certificate for the software signature. After you have the certificate, you can write the certificate into the software to be installed by signing the software, so that the software can be installed normally. The certificate is based on the serial number of the mobile phone. It's used on the computer, not installed. With the certificate for signing the software, the software that needs to be signed can be installed after it is signed.