Ghidra, the NSA's own reverse-engineering software, is now open source and freely available for download. The Agency voluntarily open-sourced the decompiler in an effort to benefit the cybersecurity community. Ghidra is a software decompiler that allows users to more easily see how a computer executes a program and is finely-tuned to be more user-friendly.
https://www.notebookcheck.net/Ghidra-the-NSA-s-homegrown-decompiler-tool-is-now-open-source.413233.0.html