PyWebAuthn

PyWebAuthn is a Python module which can be used to handle WebAuthn registration and assertion. Currently, WebAuthn is supported in Firefox, Chrome, and Edge.

Installation

pip install webauthn

Usage

Generating credential options, (to be passed to navigator.credentials.create):

make_credential_options = webauthn.WebAuthnMakeCredentialOptions(
    challenge,
    rp_name,
    rp_id,
    user_id,
    username,
    display_name,
    icon_url)

Creating a WebAuthnUser object. Used during the assertion (login) process:

webauthn_user = webauthn.WebAuthnUser(
    user.id,
    user.username,
    user.display_name,
    user.icon_url,
    user.credential_id,
    user.pub_key,
    user.sign_count,
    user.rp_id)

Generating assertion options, (to be passed to navigator.credentials.get):

webauthn_assertion_options = webauthn.WebAuthnAssertionOptions(
    webauthn_user,
    challenge)

Verifying a registration response, (result of navigator.credentials.create):

webauthn_registration_response = webauthn.WebAuthnRegistrationResponse(
    RP_ID,
    ORIGIN,
    registration_response,
    challenge,
    trust_anchor_dir,
    trusted_attestation_cert_required,
    self_attestation_permitted,
    none_attestation_permitted,
    uv_required=False)  # User Verification

try:
    webauthn_credential = webauthn_registration_response.verify()
except Exception as e:
    return jsonify({'fail': 'Registration failed. Error: {}'.format(e)})

# Create User

Verifying an assertion response, (result of navigator.credentials.get):

webauthn_user = webauthn.WebAuthnUser(
    user.ukey,
    user.username,
    user.display_name,
    user.icon_url,
    user.credential_id,
    user.pub_key,
    user.sign_count,
    user.rp_id)

webauthn_assertion_response = webauthn.WebAuthnAssertionResponse(
    webauthn_user,
    assertion_response,
    challenge,
    origin,
    uv_required=False)  # User Verification

try:
    sign_count = webauthn_assertion_response.verify()
except Exception as e:
    return jsonify({'fail': 'Assertion failed. Error: {}'.format(e)})

# Update counter.
user.sign_count = sign_count

Flask Demo

There is a Flask demo available in the flask_demo directory. Follow these steps to run the Flask web app:

cd flask_demo
pip install -r requirements.txt
python create_db.py
python app.py
Go to https://localhost:5000 in your web browser. Try registering and logging in with a compatible U2F or WebAuthn authenticator.
Profit?

Flask Demo (Docker)

To run the Flask demo with Docker:

Install Docker.
docker-compose up -d
Go to https://localhost:5000 in your web browser. Try registering and logging in with a compatible U2F or WebAuthn authenticator.

Note