Hehe, because N86 is a smart phone, it is the third edition of S60 system. In order to ensure the security of the operating system, Nokia has specially provided certificate security measures for its software to prevent malicious software from attacking the system. S60 mobile phone version 2 does not need a certificate, but your mobile phone is the third version of the system.

The so-called certificate is the echo of the mobile phone serial number. The serial number of the mobile phone is different, so is the certificate (the 15 digit that appears when you press *#06# in standby mode is the serial number)! Most software with certificates is in SIXX format, and those without certificates are generally s is.

For example, the QQ QQ20 10/0 you downloaded from QQ online is in SISX format (these softwares don't need to be signed with their own certificates). At present, there are many softwares in SIS format on the Internet, all of which are very good. However, due to the limitation of certificate, we need to sign the software visa in SIXX format (of course, some software has its own certificate in SIS format). Software without a certificate cannot be installed on a mobile phone. After getting the visa, you can install it on your mobile phone.

To sign a mobile phone, you must first have your own mobile phone certificate. You can provide a mobile phone string on Saipan to apply for a certificate, then sign the software with a signature software, and then you can install and use the software without a certificate.

XX cracking refers to cracking the mobile phone with cracking software. After cracking, you can install and use it directly, without a visa, and those softwares don't need to sign for it! This is much more convenient than software signing! Of course, this is not safe for software after visa.

Having said so much, I don't know if you probably understand. If not, please leave a message!