---
id: twofish
version: "0.3.0"
license: 3-clause BSD
license_treatment: permissive
maintenance: abandoned
---

# twofish — Bindings for the Twofish implementation by Niels Ferguson

License: permissive · Maintenance: abandoned · Downloads: 462.6K/mo

## What it is and what it does

Twofish is a Python wrapper around the Twofish block cipher, a symmetric encryption algorithm designed by Niels Ferguson. It exposes a simple API: create a Twofish instance with a binary key (0–32 bytes), then call encrypt() and decrypt() on 16-byte blocks. The library performs a self-test on import to verify the underlying C implementation.

This is a low-level cryptographic primitive, not a complete cipher system. The documentation explicitly warns that it must be used within a proper cipher mode (CTR, CBC, etc.) to be secure; using it directly on plaintext is cryptographically unsafe. The package is unmaintained since 2013 and archived, with no support for modern Python versions beyond 3.3.

Use it for:

- Legacy system integration where Twofish is mandated by existing protocols or data formats
- Educational exploration of block cipher mechanics and symmetric encryption primitives
- Decryption of historical data encrypted with Twofish in a supported cipher mode

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides Python bindings to the Twofish block cipher for encrypting and decrypting 16-byte blocks with keys up to 32 bytes.

No. The package is abandoned, unmaintained since 2013, and documented only for end-of-life Python versions (2.6–3.3). Modern Python compatibility is unverified. High install friction (compiled C extension + system library) and the explicit warning that it requires external cipher-mode wrapping make it unsuitable for new projects. Use a maintained cryptography library like cryptography or PyCryptodome instead.

## Install

pip install twofish
uv add twofish
poetry add twofish

## Installing twofish

Before you install: High install friction: the package requires a compiled C extension and the libtwofish-dev system library. The project is archived and unmaintained since 2013, with no updates for over a decade. Compatibility claims are limited to Python 2.6, 2.7, and 3.3—all end-of-life versions.

License in practice: Licensed under 3-clause BSD (permissive), allowing commercial and private use with attribution and liability disclaimer. No restrictions on redistribution or modification.

Quickstart:

pip install twofish

from twofish import Twofish
T = Twofish(b'*secret*')
encrypted = T.encrypt(b'YELLOWSUBMARINES')
decrypted = T.decrypt(encrypted)

Requires libtwofish-dev system library installed; high compilation friction. Designed for Python 2.6–3.3; compatibility with modern Python versions is unverified.

Verify before relying:

- Whether the package compiles and runs on Python 3.8 or later (only 3.3 is documented)
- Current status of the underlying Niels Ferguson Twofish implementation and any known cryptographic weaknesses
- Whether libtwofish-dev is available in current Linux distributions or requires manual installation

## Package facts

- License: 3-clause BSD (permissive)
- Python support: unspecified
- Install friction: high
- Maintenance: abandoned
- Downloads: 462.6K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

twofish encryption python, block cipher bindings, symmetric key cryptography, twofish decrypt encrypt, cryptographic library python, niels ferguson twofish, abandoned, legacy-crypto

[View on SkillFed](https://skillfed.io/packages/twofish) · [View on PyPI](https://pypi.org/project/twofish/)