That is, use Apple's personal developer account to sign the App, and the signed App will generate a URL link containing the installation package. Customers in need can bypass the Apple App Store, download the app directly from this link and run it on Apple's mobile phone. With the popularity of smart phones, more and more people use the apps in their mobile phones for social activities, entertainment, online shopping and other daily activities, which are also quietly targeted by some lawless elements, trying to evade supervision and install illegal apps into smart phones, thereby obtaining illegal benefits.

Apps provided to many customers are not formal application software, but illegal gambling and pornographic software provided by some overseas criminal groups. Because these illegal apps can't be put on the shelves in the strictly audited mobile app mall, they form download links and are directly installed on Apple phones for illegal network activities.