Python binding to the Networking and Cryptography (NaCl) library
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Latest Version

PyNaCl is a Python binding to libsodium, which is a fork of the Networking and Cryptography library. These libraries have a stated goal of improving usability, security and speed. It supports Python 2.7 and 3.3+ as well as PyPy 2.6+.



PyNaCl relies on libsodium, a portable C library. A copy is bundled with PyNaCl so to install you can run:

$ pip install pynacl

If you'd prefer to use one provided by your distribution you can disable the bundled copy during install by running:

$ SODIUM_INSTALL=system pip install pynacl

Mac OS X & Windows

PyNaCl ships as a binary wheel on OS X and Windows so all dependencies are included. Make sure you have an up-to-date pip and run:

$ pip install pynacl


  • Digital signatures
  • Secret-key encryption
  • Public-key encryption


  • 1.1.0 (UNRELEASED):
    • Dropped support for Python 2.6.
    • Added shared_key() method on Box.
    • You can now pass None to nonce when encrypting with Box or SecretBox and it will automatically generate a random nonce.
  • 1.0.1:
    • Fix an issue with absolute paths that prevented the creation of wheels.
  • 1.0:
    • PyNaCl has been ported to use the new APIs available in cffi 1.0+. Due to this change we no longer support PyPy releases older than 2.6.
    • Python 3.2 support has been dropped.
    • Functions to convert between Ed25519 and Curve25519 keys have been added.
  • 0.3.0:
    • The low-level API (nacl.c.*) has been changed to match the upstream NaCl C/C++ conventions (as well as those of other NaCl bindings). The order of arguments and return values has changed significantly. To avoid silent failures, nacl.c has been removed, and replaced with nacl.bindings (with the new argument ordering). If you have code which calls these functions (e.g. nacl.c.crypto_box_keypair()), you must review the new docstrings and update your code/imports to match the new conventions.