The third edition of S60 has greatly improved the security, and has stricter regulations on the third-party software installed and running in the system. Some operations involving mobile phone software and hardware security/personal information security are particularly restricted (for example, automatic startup of mobile phone startup is one of the restricted functions). In order to realize these "specially restricted" functions, the application must obtain a "signature". In other words, someone should be responsible for the safety of this operation! A program without any signature cannot be installed and run.

Signature: It refers to writing the contents of the certificate into a specific field of the application by using a special tool, indicating that the software has passed the signature audit. The signer is responsible for the security of the software.

Our so-called "self-signature" is actually in this way. To put it bluntly, you said you were developing software, you provided the IMEI code of your tester, and Symbian issued you a "development certificate". You use this certificate to sign your Test Software. You are responsible for your "development behavior"! That's all. In addition, the development certificate is valid for three years from the date of issuance, but there is no limit on the use time of the signed program (after the certificate expires, it can be installed by modifying the date of the mobile phone system, and then modified after installation).