Using a Vendored Argon2

python -m pip install argon2-cffi

should be all it takes.

But since argon2-cffi depends on argon2-cffi-bindings that vendors Argon2’s C code by default, it can lead to complications depending on the platform.

The C code is known to compile and work on all common platforms (including x86, ARM, and PPC). On x86, an SSE2-optimized version is used.

If something goes wrong, please try to update your cffi, pip and setuptools packages first:

python -m pip install -U cffi pip setuptools

Overall this should be the safest bet because argon2-cffi has been specifically tested against the vendored version.


Binary wheels for macOS, Windows, and Linux are provided on PyPI by argon2-cffi-bindings. With a recent-enough pip and setuptools, they should be used automatically.

Source Distribution

A working C compiler and CFFI environment are required to build the argon2-cffi-bindings dependency. If you’ve been able to compile Python CFFI extensions before, argon2-cffi should install without any problems.

Using a System-wide Installation of Argon2

If you set ARGON2_CFFI_USE_SYSTEM to 1 (and only 1), argon2-cffi-bindings will not build its bindings. However binary wheels are preferred by pip and Argon2 gets installed along with argon2-cffi anyway.

Therefore you also have to instruct pip to use a source distribution of argon2-cffi-bindings:

  python -m pip install --no-binary=argon2-cffi-bindings argon2-cffi

This approach can lead to problems around your build chain and you can run into incompatibilities between Argon2 and argon2-cffi if the latter has been tested against a different version.

It is your own responsibility to deal with these risks if you choose this path.

Available since version 18.1.0. The --no-binary option value changed in 21.2.0 due to the outsourcing of the binary bindings.

Override Automatic SSE2 Detection

Usually the build process tries to guess whether or not it should use SSE2-optimized code. Despite our best efforts, this can go wrong.

Therefore you can use the ARGON2_CFFI_USE_SSE2 environment variable to control the process:

  • If you set it to 1, argon2-cffi will build with SSE2 support.

  • If you set it to 0, argon2-cffi will build without SSE2 support.

  • If you set it to anything else, it will be ignored and argon2-cffi will try to guess.

Available since version 20.1.0.