The businessman wrote a program that Nokia needs to check and verify. This program is harmless to the user's mobile phone. If this is a good project, Nokia will sign it for them (it will cost money). Such as QQ, UCWEB and other programs.

Only certified programs can be installed on mobile phones, and programs without certification cannot be installed.

There are also some programs that are personal works or businesses don't want to spend money on certification. These programs cannot be installed without verification. However, individual users have the right to choose to install unauthenticated programs on their phones. To install these programs, users need to sign their own names.

Understand? Signing software means that the user authenticates some software to his mobile phone, so that his mobile phone can be installed (of course, if it is a virus, the user is responsible for it). The certificate is a mark on your mobile phone. After adding this mark to the program through the software, the program can be installed in your mobile phone.