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fido2

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library2.1.1pypypi✓ verified 35d ago

The `fido2` Python library provides comprehensive tools for implementing both client-side and server-side FIDO2/WebAuthn functionality. Currently at version 2.1.1, it maintains an active development pace with feature releases every few months and major versions approximately annually, ensuring compliance with the latest WebAuthn specifications (Level 3 working draft) and CTAP protocols.

auth-security
Install & Compatibility
Where this runs
tested against v2.2.0 · pip install
no network on importno background threads
Install × environment matrix
Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux
musl
py 3.103.920 runs
installs and imports cleanly · install 0.0s · import 0.132s · 35.6MB
glibc
py 3.103.920 runs
installs and imports cleanly · install 2.4s · import 0.115s · 36MB
33MB installed
● package 33MB
Code
Verified usage

Verified import paths — ran on the pinned version, not inferred.

from fido2.webauthn import AttestationObject
from fido2.webauthn import CollectedClientData

The primary verification functions are now top-level in `fido2.webauthn` for clarity.

from fido2.webauthn import verify_registration_response
from fido2.client import Fido2Client
from fido2 import cbor

This quickstart demonstrates how to verify a FIDO2 WebAuthn registration response on the server-side. It simulates receiving `clientDataJSON` and `attestationObject` from a browser and uses `fido2.webauthn.verify_registration_response` to validate them against server-generated challenge and Relying Party (RP) configuration. The example uses minimal mock data for demonstration purposes.

import os import json import base64 from fido2.webauthn import ( AttestationObject, CollectedClientData, verify_registration_response, ) from fido2 import cbor # --- Server-side configuration and stored data --- # In a real application, these would be generated and stored securely. RP_ID = os.environ.get("FIDO2_RP_ID", "example.com") RP_ORIGIN = f"https://{RP_ID}" # A challenge issued previously by the server to the client for this registration attempt # This must be a cryptographically secure random 32-byte value. CHALLENGE = base64.urlsafe_b64decode(b"uKz0s4zP6T3o-J2V-5rX_s_L4l6m-c7C8j9k0l1m2n3o4p5q6r7s8t9u0v1w2x3y=") # Example base64url-encoded bytes for a 32-byte challenge USER_ID = b"some_unique_user_id_bytes" # The user ID for whom registration was requested EXPECTED_RP_ID = RP_ID EXPECTED_ORIGINS = {RP_ORIGIN} # --- Simulate client-provided data (in a real app, these come from the browser) --- # Example: clientDataJSON received from the browser as a string client_data_json_str = f''' {{ "type": "webauthn.create", "challenge": "{base64.urlsafe_b64encode(CHALLENGE).rstrip(b'=').decode('utf-8')}", "origin": "{RP_ORIGIN}", "crossOrigin": false }} ''' # Example: AttestationObject received from the browser as base64url-encoded CBOR bytes # This is a minimal 'none' attestation for demonstration purposes. # Real attestations are more complex. attestation_object_b64url = "o2NmbXRoZJpvbmVhdHRTdG10oGhhdXRoRGF0YVjLp_hNq_D0D8x4jL17w2-5rX_s_L4l6m-c7C8j9k0l1m2n3o4p5q6r7s8t9u0v1w2x3yFkQAAAAAAAAAAAAAAAAAAAAAAwIAIAxM0k3Kz-k_D0x4jL17w2-5rX_s_L4l6m-c7C8j9k0l1m2n3o4p5q6r7s8t9u0v1w2x3yBoAAAAAAAAAAAAAAAAAAAAAADAAAAAQAg" # --- Server-side verification using fido2 library --- try: # Parse the client data and attestation object client_data = CollectedClientData(json.loads(client_data_json_str)) attestation_object = AttestationObject(base64.urlsafe_b64decode(attestation_object_b64url + "==")) # Add padding back for base64 # Verify the registration response auth_data = verify_registration_response( client_data=client_data, attestation_object=attestation_object, challenge=CHALLENGE, rp_id=EXPECTED_RP_ID, origins=EXPECTED_ORIGINS, user_id=USER_ID # In production, you would pass `trusted_attestation_public_keys` # or `attestation_callback` to validate attestation certificates. ) print("Registration successful!") print(f"Credential ID: {base64.urlsafe_b64encode(auth_data.credential_id).decode('utf-8')}") print(f"Public Key: {base64.urlsafe_b64encode(auth_data.credential_public_key).decode('utf-8')}") print(f"Signature Count: {auth_data.sign_count}") # In a real application, you would store auth_data.credential_id, # auth_data.credential_public_key, and auth_data.sign_count # associated with the user for future authentication. except Exception as e: print(f"Registration failed: {e}")
fido2 --version
Debug
Known footguns
breakingVersion 2.0.0 introduced a minimum Python version requirement of 3.10 or later.
breakingWebAuthn dataclasses (e.g., `PublicKeyCredentialRpEntity`, `AttestationObject`, `CollectedClientData`) were significantly updated in v2.0.0. Constructors now require keyword arguments only, aligning with WebAuthn Level 3. Serialization to/from dictionaries is now compatible with standardized JSON formats.
breakingThe `features.webauthn_json_mapping` flag was removed in v2.0.0. Its behavior, which enabled standardized JSON formats for WebAuthn data structures, is now the default.
breakingOld extension APIs, which were deprecated in version 1.2.0, have been removed entirely in version 2.0.0.
gotchaThe `websafe_decode` utility function (e.g., in `fido2.utils`) expects a `str` argument. Passing `bytes` was deprecated in 1.1.3 and will raise a `TypeError` in versions 2.0.0 and above.
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