zELF

Spec sheet

Purpose

zELF packs Linux ELF64 binaries to reduce their size and provide efficient runtime unpacking.Read 11 Oct 2026 · github.com

Intended users

The maker describes the project as intended for legitimate binary optimization, embedded systems, demos, education, and experimentation with ELF internals and executable packing.Read 11 Oct 2026 · github.com

Security

The maker says zELF is not designed for code obfuscation, concealment, or antivirus evasion, and its source code is openly available.Read 11 Oct 2026 · github.com

License

The project is released under GPLv3, subject to licenses of bundled components.Read 11 Oct 2026 · github.com

Archive features

It can create and unpack .zlf archives, including self-extracting archive outputs.Read 11 Oct 2026 · github.com

Archives

It can create and unpack .zlf archives, including self-extracting archive outputs.Read 11 Oct 2026 · github.com

Binary formats

It supports static and dynamic/PIE ELF64 binaries and does not support 32-bit ELF.Read 11 Oct 2026 · github.com

Binary support

It handles static and dynamic/PIE binaries, with header and segment validation.Read 11 Oct 2026 · github.com

Build and distribution

The README documents building the packer and producing .deb or .tar.gz packages; the packer must have matching target stubs available for the architecture being packed.Read 11 Oct 2026 · github.com

Build options

The release describes dynamic builds as linked against system libraries and static builds as self-contained without external dependencies.Read 11 Oct 2026 · github.com

Compression

It includes 22 compression codecs, including LZ4, LZMA, ZSTD, and LZHAM.Read 11 Oct 2026 · github.com

Downloads

The v0.91 release provides dynamic and static Linux builds for amd64 and aarch64, including Debian, Fedora/RHEL/openSUSE, and Alpine packages plus portable archives.Read 11 Oct 2026 · github.com

Executable filters

It provides BCJ and KanziEXE filters, with automatic selection via trained decision trees.Read 11 Oct 2026 · github.com

Extensibility

The maker describes zELF as modular and documents how developers can integrate additional compression codecs.Read 11 Oct 2026 · github.com

Filters and selection

It offers BCJ and KanziEXE filters, automatic selection using trained decision trees, and modes that try multiple codec and filter combinations.Read 11 Oct 2026 · github.com

License and community

The repository identifies GPLv3 as its main license and invites users to open issues, submit pull requests, or discuss ideas.Read 11 Oct 2026 · github.com

Memory limit

Some codecs can require substantial memory; the README says LZHAM uses a 512 MB dictionary and aborts if available memory or RLIMIT_AS is insufficient.Read 11 Oct 2026 · github.com

Optimization modes

Its -best mode tries three predicted codecs and its -crazy mode tries all eligible codecs to select the smallest output.Read 11 Oct 2026 · github.com

Password option

The password option stores an obfuscated FNV-1a hash in the stub.Read 11 Oct 2026 · github.com

Security limitation

The maker says zELF is not designed for code obfuscation, concealment, antivirus evasion, or malicious code distribution.Read 11 Oct 2026 · github.com

Support and contributions

The maker invites users to open issues, submit pull requests, or discuss ideas on the project.Read 11 Oct 2026 · github.com

Supported targets

It supports Linux ELF64 x86_64 and AArch64 (arm64) binaries; ELF 32-bit is unsupported.Read 11 Oct 2026 · github.com

Where Specifiction places it

• Executable Packers#24 of 286.7