First of all, thank you for contributing.

Bugs or feature requests can be posted online on the GitHub issues section of the project.

Few rules to ease code reviews and merges:

• You MUST follow the PSR-12 for coding standards.

• You MUST run the test suite (see below).

• You MUST write (or update) unit tests when bugs are fixed or features are added.

• You SHOULD write documentation.

• You MAY follow the PSR-5 and PSR-19.

We use the following branching workflow:

• Each minor version has a dedicated branch (e.g. v1.1, v1.2, v2.0, v2.1…)

• The default branch is set to the last minor version (e.g. v2.1).

To contribute use Pull Requests, please, write commit messages that make sense, and rebase your branch before submitting your PR.

Your PR should NOT be submitted to the master branch but to the last minor version branch or to another minor version in case of bug fix.

Run test suite

• install composer: curl -s http://getcomposer.org/installer | php

• install dependencies: php composer.phar install

• run tests: vendor/bin/phpunit

In the Webauthn context, there are two ceremonies:

• The attestation ceremony: it corresponds to the registration of a new authenticator,

• The assertion ceremony: it is used for the authentication of a user.

For both ceremonies, there are two steps to perform:

1. The creation of options: these options are sent to the authenticator and indicate what to do and how.

2. The response of the authenticator: after the user interacted with the authenticator, the authenticator computes a response that has to be verified.

Depending on the options and the capabilities of the authenticator, the user interaction may differ. It can be a simple touch on a button or a complete authentication using biometric means (PIN code, fingerprint, facial recognition…).

Webauthn is now supported by all main web browsers:

• Mozilla Firefox 60+ and Firefox for Android 68+

• Google Chrome 67+

• Microsoft EDGE 18+ and Microsoft EDGE Chromium 79+

• Opera 54+

• Safari 13+ and iOS Safari 13.3+

• Android Browser 76+

For more information and limitation on these browsers, please have a look at the following page: https://caniuse.com/#feat=webauthn

This framework contains several sub-packages that you don’t necessarily need. It is highly recommended to install what you need and not the whole framework.

The preferred way to install the library you need is to use composer:

composer require web-auth/webauthn-lib

Hereafter the dependency tree:

• web-auth/webauthn-lib: this is the core library. This package can be used in any PHP project or within any popular framework (Laravel, CakePHP…)

• web-auth/webauthn-symfony-bundle: this is a Symfony bundle that ease the integration of this authentication mechanism in your Symfony project.

The core library also depends on web-auth/cose-lib and web-auth/metadata-service. What are these dependencies?

web-auth/cose-lib contains several cipher algorithms and COSE key support to verify the digital signatures sent by the authenticators during the creation and authentication ceremonies. These algorithms are compliant with the RFC8152. This library can be used by any other PHP projects. At the moment only signature algorithms are available, but it is planned to add encryption algorithms.

web-auth/metadata-service provides classes to support the Fido Alliance Metadata Service. If you plan to use Attestation Statements during the creation ceremony, this service is mandatory. Please note that Attestation Statements decreases the user privacy as they may leak data that allow to identify a specific user. The use of Attestation Statements and this service are generally not recommended unless you REALLY need this information. This library can also be used by any other PHP projects.

Framework and Dependency Sizes

The total size of the core package is approximately 760ko. Hereafter the detail for each component:

• web-auth/cose-lib: 85ko

• web-auth/metadata-service: 81ko

• web-auth/webauthn-lib: 207ko

• web-auth/webauthn-symfony-bundle: 385ko

The total size of the core package + the direct dependencies is approximately 1.7Mo.

Webauthn defines an API enabling the creation and use of strong, attested, scoped, public key-based credentials by web applications, for the purpose of strongly authenticating users.

The complete specification can be found on the W3C dedicated page.

This framework contains PHP libraries and Symfony bundle to allow developers to integrate that authentication mechanism into their web applications.

Class, Constant and Property Names

Naming things may be complicated. That’s why the following rule applies on the whole framework: the name of classes, constants and properties are identical to the ones you will find in the specification.

As an example, the section 5.2.2 “Web Authentication Assertion” shows an object named AuthenticatorAssertionResponse that extends AuthenticatorResponse with the following properties:

• authenticatorData

• signature

• userHandle

  You will find EXACTLY the same structure in the PHP class provided by the library.

Supported features

• Attestation Types

  • Empty

  • Basic

  • Self

  • Private CA

  • Anonymization CA

  • Elliptic Curve Direct Anonymous Attestation (ECDAA)

• Attestation Formats

  • FIDO U2F

  • Packed

  • TPM

  • Android Key

  • Android Safetynet

  • Apple

• Token Binding support

• Cose Algorithms

  • RS1, RS256, RS384, RS512

  • PS256, PS384, PS512

  • ES256, ES256K, ES384, ES512

  • ED25519

• Extensions

  • Supported (not fully tested)

  • appid extension (compatibility with FIDO U2F authenticator)

Compatible Authenticators

The framework is already compatible with all authenticators except the ones that use ECDAA Attestation format.

The compliance of the framework is ensured by running unit and functional tests during its development.

It is also tested using the official FIDO Alliance testing tools. The status of the compliance tests are reported in this issue. At the time of writing (end of April 2021), the main features and algorithms are supported and 99% of the tests pass.

Support

I bring solutions to your problems and answer your questions.

If you really love that project, and the work I have done or if you want I prioritize your issues, then you can help me out for a couple of🍻 or more!

Contributing

Requests for new features, bug fixed and all other ideas to make this framework useful are welcome.

If you feel comfortable writing code, you could try to fix opened issues where help is wanted or those that are easy to fix.

Do not forget to follow these best practices.

User verification may be instigated through various authorization gesture modalities: a touch plus PIN code, password entry, or biometric recognition (presenting a fingerprint). The intent is to be able to distinguish individual users.

Eligible authenticators are filtered and only capable of satisfying this requirement will interact with the user.

Possible user verification values are:

• required: this value indicates that the application requires user verification for the operation and will fail the operation if the response does not have the UV flag set.

• preferred: this value indicates that the application prefers user verification for the operation if possible, but will not fail the operation if the response does not have the UV flag set.

• discouraged: this value indicates that the application does not want user verification employed during the operation (e.g.,in the interest of minimizing disruption to the user interaction flow).

Public constants are provided by AuthenticatorSelectionCriteria.

• AuthenticatorSelectionCriteria::USER_VERIFICATION_REQUIREMENT_REQUIRED

• AuthenticatorSelectionCriteria::USER_VERIFICATION_REQUIREMENT_PREFERRED

• AuthenticatorSelectionCriteria::USER_VERIFICATION_REQUIREMENT_DISCOURAGED

An Authenticator is a cryptographic entity used to generate a public key credential and registered by a Relying Party (i.e. an application). This public key is used to authenticate by potentially verifying a user in the form of an authentication assertion and other data.

Authenticators may have additional features such as PIN code or biometric sensors (fingerprint, facial recognition…) that offer user verification.

Roaming Authenticators

The roaming authenticator may have different forms. The most common form is a USB device the user plugs into its computer. It can be a paired Bluetooth device or a card with NFC capabilities.

Authenticators of this class are removable from, and can "roam" among, client devices.

Platform Authenticators

A platform authenticator is usually not removable from the client device. For example an Android smartphone or a Windows 10 computer with the associated security chips can act as an authenticator.

After the registration of an authenticator, you will get a Public Key Credential Source object. It contains all the credential data needed to perform user authentication and much more.

Each Credential Source is managed using the Public Key Credential Source Repository.

The library does not provide any concrete implementation. It is up to you to create it depending on your application constraints. This only constraint is that your repository class must implement the interface Webauthn\PublicKeyCredentialSourceRepository.

The PublicKeyCredentialSourceRepository interface requires the following methods to be implemented:

• public function findOneByCredentialId(string $publicKeyCredentialId): ?PublicKeyCredentialSource; : thie method retreive a key source object from the credential ID.

• public function findAllForUserEntity(PublicKeyCredentialUserEntity $publicKeyCredentialUserEntity): array;: this method lists all key sources associated to the user entity

• public function saveCredentialSource(PublicKeyCredentialSource $publicKeyCredentialSource): void;: this method saves the key source in your storage (files, database...)

Browsers may support the Token Binding protocol (see RFC 8471). This protocol defines a way to bind a token (the Responses in the Webauthn context) to the underlying TLS layer.

When receiving a Webauthn Response, the property tokenBinding in the Webauthn\CollectedClientData object has one of the following values:

• null: the token binding is not supported by the browser

• "supported": the browser supports token binding, but no negotiation was performed during the communication

• "present": the browser supports token binding, and it is present in the response. The token binding ID is provided.

This feature is not yet implemented in the library, but you can decide how the library will react in case of the presence of the token binding ID.

The library provides two concrete classes for the moment:

• Webauthn\TokenBinding\IgnoreTokenBindingHandler: the library will ignore the token binding (recommended),

• Webauthn\TokenBinding\TokenBindingNotSupportedHandler: the library will throw an exception if the token binding is present.

You can change this behavior by creating your own implementation. The handler must implement the interface Webauthn\TokenBinding\TokenBindingHandler.

The mechanism for generating public key credentials, as well as requesting and generating Authentication assertions, can be extended to suit particular use cases. Each case is addressed by defining a registration extension.

Standard extensions are usually listed in the dedicated IANA Registry available at https://www.iana.org/assignments/webauthn/webauthn.xhtml

Among the available extensions, you have:

• loc: The location registration extension and authentication extension provides the client device's current location to the WebAuthn Relying Party, if supported by the client platform and subject to user consent.

• hmac-secret: This registration extension and authentication extension enables the platform to retrieve a symmetric secret scoped to the credential from the authenticator.

• minPinLength: This registration extension returns the current minimum PIN length value to the Relying Party.

Attestation Statement

During the Attestation Ceremony (i.e. the registration of the authenticator), you can ask for the Attestation Statement of the authenticator. The Attestation Statements have one of the following types:

• None (none): no Attestation Statement is provided

• Basic Attestation (basic): Authenticator’s attestation key pair is specific to an authenticator model.

• Surrogate Basic Attestation (or Self Attestation - self): Authenticators that have no specific attestation key use the credential private key to create the attestation signature

• Attestation CA (AttCA): Authenticators are based on a Trusted Platform Module (TPM). They can generate multiple attestation identity key pairs (AIK) and requests an Attestation CA to issue an AIK certificate for each.

• Anonymization CA (AnonCA): Authenticators use an Anonymization CA, which dynamically generates per-credential attestation certificates such that the attestation statements presented to Relying Parties do not provide uniquely identifiable information.

• Elliptic Curve based Direct Anonymous Attestation (ECDAA): Authenticator receives direct anonymous attestation (DAA) credentials from a single DAA-Issuer. These DAA credentials are used along with blinding to sign the attested credential data.

Metadata Statement

The Metadata Statements are issued by the manufacturers of the authenticators. These statements contain details about the authenticators (supported algorithms, biometric capabilities...) and all the necessary information to verify the Attestation Statements generated during the attestation ceremony.

There are several possible sources to get these Metadata Statements. The main source is the FIDO Alliance Metadata Service that allows fetching statements on-demand, but some of them may be provided by other means.

The Relying Party (or rp) corresponds to the application that will ask for the user to interact with the authenticator.

The library provides a simple class to handle the rp information: Webauthn\PublicKeyCredentialRpEntity.

<?php

use Webauthn\PublicKeyCredentialRpEntity;

$rpEntity = PublicKeyCredentialRpEntity::create(
    'ACME Webauthn Server' // The application name
);

This $rpEntity object will be useful for the next steps.

Relying Party ID

In the example above, we created a simple relying party object with it’s name. The relying party may also have an ID that corresponds to the domain applicable for that rp. By default, the relying party ID is null i.e. the current domain will be used.

It may be useful to specify the rp ID, especially if your application has several sub-domains. The rp ID can be set during the creation of the object as 2nd constructor parameter.

<?php

use Webauthn\PublicKeyCredentialRpEntity;

$rpEntity = PublicKeyCredentialRpEntity::create(
    'ACME Webauthn Server', // The application name
    'acme.com'              // The application ID = the domain
);

The rp ID shall be the domain of the application without the scheme, userinfo, port, path, user…. IP addresses are not allowed either.

How to determine the Relying Party ID?

The Relying Party ID should be determined depending on the common URLs for your web application.

If you have a web application that can be reached at https://m.my-app.com (for mobiles) and https://my-app.com or https://www.my-app.com (for other devices), your Relying Party ID should be my-app.com.

If the domain is shared between sub-projects, the rp ID should be limited to that sub-projects.

For example, a web site is located at https://(www.)site1.host.com and another at https://(www.)site2.host.com, then the Relying Party IDs should be site1.host.com and site2.host.com respectively. If you set host.com, there is a risk that users from site1.host.com can log in at site2.host.com.

Relying Party Icon

Your application may also have a logo. You can indicate this logo as third argument. Please note that for safety reason this icon is a priori authenticated URL i.e. an image that uses the data scheme.

<?php

use Webauthn\PublicKeyCredentialRpEntity;

$rpEntity = PublicKeyCredentialRpEntity::create(
    'ACME Webauthn Server',
    'acme.com',
    'data:image/png;base64,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'
);

User Entity

A User Entity object represents a user in the Webauthn context. It has the following constraints:

• The user ID must be unique and must be a string,

• The username must be unique,

Hereafter a minimalist example of user entity:

<?php

use Webauthn\PublicKeyCredentialUserEntity;

$userEntity = PublicKeyCredentialUserEntity::create(
    'john.doe',                             // Username
    'ea4e7b55-d8d0-4c7e-bbfa-78ca96ec574c', // ID
    'John Doe'                              // Display name
);

As for the rp Entity, the User Entity may have an icon. This icon must also be secured.

<?php

use Webauthn\PublicKeyCredentialUserEntity;

$userEntity = PublicKeyCredentialUserEntity::create(
    'john.doe',
    'ea4e7b55-d8d0-4c7e-bbfa-78ca96ec574c',
    'John Doe',
    'data:image/png;base64,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'
);

User Entity Repository

The User Entity Repository manages all Webauthn users of your application.

There is no interface to implement or abstract class to extend so that it should be easy to integrate it in your application. You may already have a user repository.

It shall be noted that the Symfony bundle will need a user entity repository. This service shall implement Webauthn\Bundle\Repository\PublicKeyCredentialUserEntityRepository.

The methods required by the interface are as follow:

• public function findOneByUsername(string $username): ?PublicKeyCredentialUserEntity; This method tries to find out a user entity from the username.

• public function findOneByUserHandle(string $userHandle): ?PublicKeyCredentialUserEntity; This method tries to find out a user entity from the user handle i.e. the user ID.

• public function generateNextUserEntityId(): string; This method creates a user entity ID. Note that this method SHALL NOT save that ID. Its main purpose generate a unique ID that could be used for a user entity object at a later stage.

• public function saveUserEntity(PublicKeyCredentialUserEntity $userEntity): void; This method saves the user entity. If the user entity already exists, it should throw an exception.

You will interact with the authenticators through an HTML page and Javascript using the Webauthn API.

A package is available at https://github.com/web-auth/webauthn-helper. It contains functions that will ease the interaction with the login or the registration endpoints.

Installation

You can use npm or yarn to install the package:

npm i @web-auth/webauthn-helper
#or
yarn add @web-auth/webauthn-helper

Registration

// Import the registration hook
import {useRegistration} from 'webauthn-helper';

// Create your register function.
// By default the urls are "/register" and "/register/options"
// but you can change those urls if needed.
const register = useRegistration({
    actionUrl: '/api/register',
    optionsUrl: '/api/register/options'
});


// We can call this register function whenever we need (e.g. form submission)
register({
    username: 'john.doe',
    displayName: 'JD'
})
    .then((response) => console.log('Registration success'))
    .catch((error) => console.log('Registration failure'))
;

Additional options can be set during the registration process. See the section “Deep into the framework” to know more. Hereafter another example:

register({
    username: 'john.doe',
    displayName: 'JD',
    attestation: 'none',
    authenticatorSelection: {
        authenticatorAttachment: 'platform',
        requireResidentKey: true,
        userVerification: 'required'
    }
})
    .then((response) => console.log('Registration success'))
    .catch((error) => console.log('Registration failure'))
;

Authentication

// Import the login hook
import {useLogin} from 'webauthn-helper';

// Create your login function.
// By default the urls are "/login" and "/login/options"
// but you can change those urls if needed.
const login = useLogin({
    actionUrl: '/api/login',
    optionsUrl: '/api/login/options'
});


// We can call this login function whenever we need (e.g. form submission)
login({
    username: 'john.doe'
})
    .then((response) => console.log('Authentication success'))
    .catch((error) => console.log('Authentication failure'))
;

As done during the registration, additional options are available. See the section “Deep into the framework” to know more. Hereafter another example:

login({
    username: 'john.doe',
    userVerification: 'required'
})
    .then((response) => console.log('Authentication success'))
    .catch((error) => console.log('Authentication failure'))
;

During this step, your application will send a challenge to the device. The device will resolve this challenge by adding information and digitally signing the data.

The application will check the response from the device and get its credential ID. This ID will be used for further authentication requests.

Creation Request

To associate a device to a user, you need to instantiate a Webauthn\PublicKeyCredentialCreationOptions object.

It will need:

• The Relying Party

• The User data

• A challenge (random binary string)

• A list of supported public key parameters i.e. an algorithm list (at least one)

Optionally, you can customize the following parameters:

• A timeout

• A list of public key credential to exclude from the registration process

• The Authenticator Selection Criteria

• Attestation conveyance preference

• Extensions

Let’s see an example of the PublicKeyCredentialCreationOptions object. The following example is a possible Public Key Creation page for a dummy user "@cypher-Angel-3000".

<?php

declare(strict_types=1);

use Cose\Algorithms;
use Webauthn\AuthenticatorSelectionCriteria;
use Webauthn\PublicKeyCredentialDescriptor;
use Webauthn\PublicKeyCredentialCreationOptions;
use Webauthn\PublicKeyCredentialParameters;
use Webauthn\PublicKeyCredentialRpEntity;
use Webauthn\PublicKeyCredentialUserEntity;

// RP Entity i.e. the application
$rpEntity = PublicKeyCredentialRpEntity::create(
    'My Super Secured Application', //Name
    'foo.example.com',              //ID
    null                            //Icon
);

// User Entity
$userEntity = PublicKeyCredentialUserEntity::create(
    '@cypher-Angel-3000',                   //Name
    '123e4567-e89b-12d3-a456-426655440000', //ID
    'Mighty Mike',                          //Display name
    null                                    //Icon
);

// Challenge
$challenge = random_bytes(16);

// Public Key Credential Parameters
$publicKeyCredentialParametersList = [
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_ES256),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_ES256K),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_ES384),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_ES512),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_RS256),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_RS384),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_RS512),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_PS256),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_PS384),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_PS512),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_ED256),
    PublicKeyCredentialParameters::create('public-key', Algorithms::COSE_ALGORITHM_ED512),
];

$publicKeyCredentialCreationOptions =
    PublicKeyCredentialCreationOptions::create(
        $rpEntity,
        $userEntity,
        $challenge,
        $publicKeyCredentialParametersList,
    )
;

You can change the default values for each and all options

$publicKeyCredentialCreationOptions =
    PublicKeyCredentialCreationOptions::create(
        $rpEntity,
        $userEntity,
        $challenge,
        $publicKeyCredentialParametersList,
    )
    ->setTimeout(30_000)
    ->excludeCredentials(...$excludedPublicKeyDescriptors)
    ->setAuthenticatorSelection(AuthenticatorSelectionCriteria::create())
    ->setAttestation(PublicKeyCredentialCreationOptions::ATTESTATION_CONVEYANCE_PREFERENCE_NONE)
;

Creation Response

What you receive must be a JSON object that looks like as follow:

{
    "id":"KVb8CnwDjpgAo[…]op61BTLaa0tczXvz4JrQ23usxVHA8QJZi3L9GZLsAtkcVvWObA",
    "type":"public-key",
    "rawId":"KVb8CnwDjpgAo[…]rQ23usxVHA8QJZi3L9GZLsAtkcVvWObA==",
    "response":{
        "clientDataJSON":"eyJjaGFsbGVuZ2UiOiJQbk1hVjBVTS[…]1iUkdHLUc4Y3BDSdGUifQ==",
        "attestationObject":"o2NmbXRmcGFja2VkZ2F0dFN0bXSj[…]YcGhf"
    }
}

There are two steps to perform with this object:

• Load the data

• Verify it with the creation options set above

Data Loading

Now that all components are set, we can load the data we receive using the Public Key Credential Loader service (variable $publicKeyCredential).

<?php

declare(strict_types=1);

$data = '
{
    "id":"KVb8CnwDjpgAo[…]op61BTLaa0tczXvz4JrQ23usxVHA8QJZi3L9GZLsAtkcVvWObA",
    "type":"public-key",
    "rawId":"KVb8CnwDjpgAo[…]rQ23usxVHA8QJZi3L9GZLsAtkcVvWObA==",
    "response":{
        "clientDataJSON":"eyJjaGFsbGVuZ2UiOiJQbk1hVjBVTS[…]1iUkdHLUc4Y3BDSdGUifQ==",
        "attestationObject":"o2NmbXRmcGFja2VkZ2F0dFN0bXSj[…]YcGhf"
    }
}';

$publicKeyCredential = $publicKeyCredentialLoader->load($data);

If no exception is thrown, you can go to the next step: the verification.

Response Verification

Now we have a fully loaded Public Key Credential object, but we need now to make sure that:

1. The authenticator response is of type AuthenticatorAttestationResponse

2. This response is valid.

The first step is easy to perform:

<?php

declare(strict_types=1);

use Webauthn\AuthenticatorAttestationResponse;

$authenticatorAttestationResponse = $publicKeyCredential->getResponse();
if (!$authenticatorAttestationResponse instanceof AuthenticatorAttestationResponse) {
    //e.g. process here with a redirection to the public key creation page. 
}

The second step is the verification against

• The Public Key Creation Options we created earlier,

• The HTTP request

The Authenticator Attestation Response Validator service (variable $authenticatorAttestationResponseValidator) will check everything for you: challenge, origin, attestation statement and much more.

<?php

declare(strict_types=1);

use Nyholm\Psr7\Factory\Psr17Factory;
use Nyholm\Psr7Server\ServerRequestCreator;

$psr17Factory = new Psr17Factory();
$creator = new ServerRequestCreator(
    $psr17Factory, // ServerRequestFactory
    $psr17Factory, // UriFactory
    $psr17Factory, // UploadedFileFactory
    $psr17Factory  // StreamFactory
);

$serverRequest = $creator->fromGlobals();

$publicKeyCredentialSource = $authenticatorAttestationResponseValidator->check(
    $authenticatorAttestationResponse,
    $publicKeyCredentialCreationOptions,
    $serverRequest
);

If no exception is thrown, the response is valid. You can store the Public Key Credential Source ($publicKeyCredentialSource) and associate it to the user entity.

During this step, your application will send a challenge to the list of registered devices of the user. The security token will resolve this challenge by adding information and digitally signing the data.

Assertion Request

To perform a user authentication using a security device, you need to instantiate a Webauthn\PublicKeyCredentialRequestOptions object.

Let’s say you want to authenticate the user we used earlier. This options object will need:

• A challenge (random binary string)

• The list with the allowed credentials (may be an option in certain circumstances)

Optionally, you can customize the following parameters:

• A timeout

• The Relying Party ID i.e. your application domain

• The user verification requirement

• Extensions

The PublicKeyCredentialRequestOptions object is designed to be easily serialized into a JSON object. This will ease the integration into an HTML page or through an API endpoint.

Allowed Credentials

The user trying to authenticate must have registered at least one device. For this user, you have to get all Webauthn\PublicKeyCredentialDescriptor associated to his account.

// We gather all registered authenticators for this user
$registeredAuthenticators = $publicKeyCredentialSourceRepository->findAllForUserEntity($userEntity);

// We don’t need the Credential Sources, just the associated Descriptors
$allowedCredentials = array_map(
    static function (PublicKeyCredentialSource $credential): PublicKeyCredentialDescriptor {
        return $credential->getPublicKeyCredentialDescriptor();
    },
    $registeredAuthenticators
);

Example

<?php

declare(strict_types=1);

use Webauthn\PublicKeyCredentialDescriptor;
use Webauthn\PublicKeyCredentialRequestOptions;
use Webauthn\PublicKeyCredentialSource;

// List of registered PublicKeyCredentialDescriptor classes associated to the user
$registeredAuthenticators = $publicKeyCredentialSourceRepository->findAllForUserEntity($userEntity);
$allowedCredentials = array_map(
    static function (PublicKeyCredentialSource $credential): PublicKeyCredentialDescriptor {
        return $credential->getPublicKeyCredentialDescriptor();
    },
    $registeredAuthenticators
);

// Public Key Credential Request Options
$publicKeyCredentialRequestOptions = 
    PublicKeyCredentialRequestOptions::create(
        random_bytes(32) // Challenge
    )
    ->allowCredentials(...$allowedCredentials)
;

User Verification

<?php

declare(strict_types=1);

use Webauthn\PublicKeyCredentialDescriptor;
use Webauthn\PublicKeyCredentialRequestOptions;
use Webauthn\PublicKeyCredentialSource;

// List of registered PublicKeyCredentialDescriptor classes associated to the user
$registeredAuthenticators = $publicKeyCredentialSourceRepository->findAllForUserEntity($userEntity);
$allowedCredentials = array_map(
    static function (PublicKeyCredentialSource $credential): PublicKeyCredentialDescriptor {
        return $credential->getPublicKeyCredentialDescriptor();
    },
    $registeredAuthenticators
);

// Public Key Credential Request Options
$publicKeyCredentialRequestOptions = 
    PublicKeyCredentialRequestOptions::create(
        random_bytes(32) // Challenge
    )
    ->setUserVerification(
        PublicKeyCredentialRequestOptions::USER_VERIFICATION_REQUIREMENT_REQUIRED
    )
;

Extensions

<?php

declare(strict_types=1);

use Webauthn\PublicKeyCredentialRequestOptions;

// List of registered PublicKeyCredentialDescriptor classes associated to the user
$registeredAuthenticators = $publicKeyCredentialSourceRepository->findAllForUserEntity($userEntity);
$allowedCredentials = array_map(
    static function (PublicKeyCredentialSource $credential): PublicKeyCredentialDescriptor {
        return $credential->getPublicKeyCredentialDescriptor();
    },
    $registeredAuthenticators
);

// Public Key Credential Request Options
$publicKeyCredentialRequestOptions = 
    PublicKeyCredentialRequestOptions::create(
        random_bytes(32) // Challenge
    )
    ->addExtension(
        AuthenticationExtension::create('loc', true),
        AuthenticationExtension::create('txAuthSimple', 'Please log in with a registered authenticator'),
    )
;

Response Handling

The way you receive this response is out of scope of this library. In the previous example, the data is part of the query string, but it can be done through a POST request body or a request header.

What you receive must be a JSON object that looks like as follows:

{
    "id":"KVb8CnwDjpgAo[…]op61BTLaa0tczXvz4JrQ23usxVHA8QJZi3L9GZLsAtkcVvWObA",
    "type":"public-key",
    "rawId":"KVb8CnwDjpgAo[…]rQ23usxVHA8QJZi3L9GZLsAtkcVvWObA==",
    "response":{
        "clientDataJSON":"eyJjaGFsbGVuZ2UiOiJQbk1hVjBVTS[…]1iUkdHLUc4Y3BDSdGUifQ==",
        "authenticatorData":"Y0EWbxTqi9hWTO[…]4aust69iUIzlwBfwABDw==",
        "signature":"MEQCIHpmdruQLs[…]5uwbtlPNOFM2oTusx2eg==",
        "userHandle":""
    }
}

There are two steps to perform with this object:

• Load the data

• Verify the loaded data against the assertion options set above

Data Loading

<?php

declare(strict_types=1);

$data = '
{
    "id":"KVb8CnwDjpgAo[…]op61BTLaa0tczXvz4JrQ23usxVHA8QJZi3L9GZLsAtkcVvWObA",
    "type":"public-key",
    "rawId":"KVb8CnwDjpgAo[…]rQ23usxVHA8QJZi3L9GZLsAtkcVvWObA==",
    "response":{
        "clientDataJSON":"eyJjaGFsbGVuZ2UiOiJQbk1hVjBVTS[…]1iUkdHLUc4Y3BDSdGUifQ==",
        "attestationObject":"o2NmbXRmcGFja2VkZ2F0dFN0bXSj[…]YcGhf"
    }
}';

$publicKeyCredential = $publicKeyCredentialLoader->load($data);

Response Verification

Now we have a fully loaded Public Key Credential object, but we need now to make sure that:

1. The authenticator response is of type AuthenticatorAssertionResponse

2. This response is valid.

The first is easy to perform:

<?php

declare(strict_types=1);

use Webauthn\AuthenticatorAssertionResponse;

$authenticatorAssertionResponse = $publicKeyCredential->getResponse();
if (!$authenticatorAssertionResponse instanceof AuthenticatorAssertionResponse) {
    //e.g. process here with a redirection to the public key login/MFA page. 
}

The second step is the verification against the Public Key Assertion Options we created earlier.

The Authenticator Assertion Response Validator service (variable $authenticatorAssertionResponseValidator) will check everything for you.

<?php

declare(strict_types=1);

use Symfony\Component\HttpFoundation\Request;

$request = Request::createFromGlobals();

$userHandle = $userEntity->getId();
$publicKeyCredentialSource = $authenticatorAssertionResponseValidator->check(
    $publicKeyCredential->getRawId(),
    $authenticatorAssertionResponse,
    $publicKeyCredentialRequestOptions,
    $request,
    $userHandle