Reverse Engineering

In short: Reverse engineering examines a finished program or device to understand how it works.

In more detail: You only have the result (for example an executable file) and reconstruct its logic and structure from it.

In Depth

Tools

Disassemblers and decompilers (Ghidra, IDA), debuggers, network capture. See assembly.

Use

Analysis of malware, checking for vulnerabilities, compatibility, recovery of lost code.

Law

In Germany § 69e UrhG permits decompilation under narrow conditions (interoperability). Licence terms may forbid more.

See also: Malware, Assembly, Forensics, Penetration Testing