1)APKtool

2)dex2jar

3)jd-gui

4) Signature tool

Of course, there are many decompilation tools, and you can search by yourself as needed.

Before the app is released, it is best to scan and strengthen it. Application scanning can locate risk codes through static code analysis and dynamic data tracking (at present, many only tell APK packets that there are risks) and monitor the abnormal behavior of sensitive data.

Reinforcement can protect its own core code algorithm to a certain extent, improve the difficulty of cracking/piracy/secondary packaging, and alleviate code injection/dynamic debugging/memory injection attacks.

But it also affects the compatibility of the application. If the reinforcement technology is not good, it will also affect the running efficiency of the program.

There are many third-party reinforcement platforms on the market at present. If new applications need to be scanned or hardened before release, you can try them for free, such as Tencent Royal Security. I suggest you scan it first.