Three objects are needed in the process of reinforcement: 1, Apk (source Apk)2, shell program Apk (responsible for decrypting Apk) 3, and encryption tool (encrypting source Apk and merging shell Dex into new Dex). The main steps are as follows: we get the Apk to be encrypted and our own shell program Apk, and then encrypt the source Apk with encryption algorithm and merge the shell Apk to get a new Dex file. Finally, replace the dex file in the shell program to get a new Apk, so this new Apk is also called the shell program Apk. It is not a complete Apk program. Its main job is to decrypt the source Apk and then load it to make it run normally.