llvm-obfuscator

LLVM New Pass Manager plugin with obfuscation transforms (instruction substitution, MBA, bogus control flow, control-flow flattening, string encryption, and others). Built against LLVM 20.

IDA demo (Hex-Rays): clean · obfuscated

Requirements

• CMake ≥ 3.20, Ninja (or another generator)
• LLVM 20 development packages (e.g. llvm-20-dev, clang-20, opt-20 on Debian/Ubuntu)
• Adjust LLVM_DIR below if your install path differs

Build

mkdir -p build && cd build
cmake -G Ninja -DLLVM_DIR=/usr/lib/llvm-20/lib/cmake/llvm ..
ninja

This produces build/passes/obfuscator.so, a loadable pass plugin for opt / clang.

Standalone module (Rust)

For a standalone .so that does not link libLLVM (for -Z llvm-plugins with rustc), add -DOBFUSCATOR_STANDALONE_MODULE=ON to the CMake line above. Prebuilt obfuscator-x86_64-unknown-linux-gnu.so is on GitHub Releases. See rust-integration/README.md and rust-integration/example-crate/.

Quick setup: from the repo root run bash rust-integration/setup.sh (Linux/WSL) or .\rust-integration\setup.ps1 on Windows (downloads the plugin; run cargo from WSL or Linux).

Rust obfuscation needs Linux x86_64 or WSL and a nightly whose LLVM matches the plugin (LLVM 20 today). Stock Windows rustup usually cannot load the plugin; build obfuscated Rust from Linux/WSL.

Windows DLL for opt: same CMake with MSVC, -DOBFUSCATOR_STANDALONE_MODULE=ON; output is obfuscator.dll under passes/ (or passes/Release/). Example: opt --load-pass-plugin=obfuscator.dll --passes=instsub -S in.ll -o out.ll. Prebuilt obfuscator-x86_64-pc-windows-msvc.dll may be on Releases.

Tests

From the repo root after building:

./tests/run_tests.sh

Or use CMake’s test runner:

cd build && ctest

Obfuscate a C file

With the default build layout:

./scripts/obfuscate.sh path/to/source.c

Use -p to pick passes (comma-separated); run ./scripts/obfuscate.sh -h for options.