Reference: https://blog.csdn.net/sun19880421/article/details/68070696
https://blog.csdn.net/mydreamremindme/article/details/51372391< /p>
Summary:
1. Preparation
1) Download the LuaJIT source code (LuaJIT-2.1.0-beta3 for 64-bit Version)
2) Install visual studio C++
2. Compile
1) Open the command line tool of visual studio: 
2) Use vs command line tool to cd to luajit src directory
3) 32-bit execution command: msvcbuild.bat
64-bit execution command: msvcbuild.bat gc64
Compile lua51.dll , Luajit.exe
3. Copy lua51.dll, luajit.exe and the jit folder in the compilation directory to an encrypted folder, such as:
4. Use in unity Encrypt the code: