Webauthn Server
To launch a Webauthn server, you will need the following components:
That’s a lot off services! But don’t worry, as their configuration is the same for all your application, you just have to set them once. Let’s see all of these in the next sections.
Every Creation Responses contain an Attestation Statement. This attestation contains data regarding the authenticator depending on several factors such as its manufacturer and model, what you asked in the options, the capabilities of the browser or what the user allowed.
The user may refuse to send information about the security token for privacy reasons.Hereafter the types of attestations you may have:
The following attestation types are supported. Note that you should only use the
none one unless you have specific needs described in the dedicated page.none: no attestation is provided.fido-u2f: for non-FIDO2 compatible devices (old FIDO / U2F security tokens).packed: generally used by authenticators with limited resources (e.g. secure elements). It uses a very compact but still extensible encoding method.android key: commonly used by old or disconnected Android devices.android safety net: for new Android devices like smartphones.trusted platform module: for devices with built-in security chips.apple: for Apple devices
<?php
declare(strict_types=1);
use Webauthn\AttestationStatement\AttestationStatementSupportManager;
use Webauthn\AttestationStatement\NoneAttestationStatementSupport;
// The manager will receive data to load and select the appropriate
$attestationStatementSupportManager = AttestationStatementSupportManager::create();
$attestationStatementSupportManager->add(NoneAttestationStatementSupport::create());
The Android SafetyNet Attestation API is deprecated. Full turndown is planned in June 2024. More information at https://developer.android.com/training/safetynet/deprecation-timeline
This object will load the Attestation statements received from the devices. It will need the Attestation Statement Support Manager created above.
<?php
declare(strict_types=1);
use Webauthn\AttestationStatement\AttestationObjectLoader;
$attestationObjectLoader = AttestationObjectLoader::create(
$attestationStatementSupportManager
);
This object will load the Public Key using from the Attestation Object.
<?php
declare(strict_types=1);
use Webauthn\PublicKeyCredentialLoader;
$publicKeyCredentialLoader = PublicKeyCredentialLoader::create(
$attestationObjectLoader
);
If you use extensions, you may need to check the value returned by the security devices. This behaviour is handled by an Extension Output Checker Manager.
<?php
declare(strict_types=1);
use Webauthn\AuthenticationExtensions\ExtensionOutputCheckerHandler;
$extensionOutputCheckerHandler = ExtensionOutputCheckerHandler::create();
You can add as many extension checkers as you want. Each extension checker must implement
Webauthn\AuthenticationExtensions\ExtensionOutputChecker and throw a Webauthn\AuthenticationExtensions\ExtensionOutputError in case of an error.The Webauthn data verification is based on cryptographic signatures and thus you need to provide cryptographic algorithms to perform those checks.
There is no mandatory algorithm list, however, we recommend the following as minimum list:
<?php
declare(strict_types=1);
use Cose\Algorithm\Manager;
use Cose\Algorithm\Signature\ECDSA\ES256;
use Cose\Algorithm\Signature\RSA\RS256;
$algorithmManager = Manager::create()
->add(
ES256::create(),
RS256::create()
)
;
The order is important. By adding
ES256 first, the relyaing party prefers an ES256 credential. Browsers are eager to satisfy preferences.The complete list of supported algorithms:
<?php
declare(strict_types=1);
use Cose\Algorithm\Manager;
use Cose\Algorithm\Signature\ECDSA\ES256;
use Cose\Algorithm\Signature\ECDSA\ES256K;
use Cose\Algorithm\Signature\ECDSA\ES384;
use Cose\Algorithm\Signature\ECDSA\ES512;
use Cose\Algorithm\Signature\EdDSA\Ed256;
use Cose\Algorithm\Signature\EdDSA\Ed512;
use Cose\Algorithm\Signature\RSA\PS256;
use Cose\Algorithm\Signature\RSA\PS384;
use Cose\Algorithm\Signature\RSA\PS512;
use Cose\Algorithm\Signature\RSA\RS256;
use Cose\Algorithm\Signature\RSA\RS384;
use Cose\Algorithm\Signature\RSA\RS512;
$algorithmManager = Manager::create()
->add(
ES256::create(),
ES256K::create(),
ES384::create(),
ES512::create(),
RS256::create(),
RS384::create(),
RS512::create(),
PS256::create(),
PS384::create(),
PS512::create(),
Ed256::create(),
Ed512::create(),
)
;
This object is what you will directly use when receiving Attestation Responses (authenticator registration).
<?php
declare(strict_types=1);
use Webauthn\AuthenticatorAttestationResponseValidator;
$authenticatorAttestationResponseValidator = AuthenticatorAttestationResponseValidator::create(
$attestationStatementSupportManager,
null, //Deprecated Public Key Credential Source Repository. Please set null.
null, //Deprecated Token Binding Handler. Please set null.
$extensionOutputCheckerHandler
);
This object is what you will directly use when receiving Assertion Responses (user authentication).
<?php
declare(strict_types=1);
use Webauthn\AuthenticatorAssertionResponseValidator;
$authenticatorAssertionResponseValidator = AuthenticatorAssertionResponseValidator::create(
null, //Deprecated Public Key Credential Source Repository. Please set null.
null, //Deprecated Token Binding Handler. Please set null.
$extensionOutputCheckerHandler, // The extension output checker handler
$algorithmManager // The COSE Algorithm Manager
);
Last modified 4d ago