Register Authenticators

As described in the previous pages, you need to create a PublicKeyCredentialCreationOptions object to register new authenticators. You can create this object using the .... But there is another way to do that.

The bundle provides a factory and manages profiles to ease the creation of the options. The factory is available as a public service: Webauthn\Bundle\Service\PublicKeyCredentialCreationOptionsFactory. To use it, you must first create a least one profile in your configuration file.

app/config/webauthn.yaml

webauthn:
    creation_profiles:
        acme: #Unique name of the profile
            rp: # rp stands for Relying Party
                name: 'ACME Webauthn Server'
                id: 'acme.com'
                icon: 'data:image/png;base64,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'

Plain Text

The name is mandatory ; other options are null by default.

The option id is highly recommended. See this page for acceptable values.

With this profile, now we can create options with the following code lines:

use Webauthn\Bundle\Service\PublicKeyCredentialCreationOptionsFactory;
use Webauthn\PublicKeyCredentialUserEntity;

$userEntity = new PublicKeyCredentialUserEntity(
    'john.doe',
    'ea4e7b55-d8d0-4c7e-bbfa-78ca96ec574c',
    'John Doe'
);

$publicKeyCredentialCreationOptions = $container
    ->get(PublicKeyCredentialCreationOptionsFactory::class)
    ->create('acme', $userEntity)
;

Challenge Length

By default, the length of the challenge is 32 bytes. You may need to select a smaller or higher length. This length can be configured for each profile:

app/config/webauthn.yaml

webauthn:
    creation_profiles:
        acme:
            rp:
                name: 'ACME Webauthn Server'
            challenge_length: 16

Timeout

The default timeout is set to 60 seconds (60 000 milliseconds). You can change this value as follow:

app/config/webauthn.yaml

webauthn:
    creation_profiles:
        acme:
            rp:
                name: 'ACME Webauthn Server'
            timeout: 30000

Authenticator Selection Criteria

This set of options allows you to select authenticators depending on their capabilities. The values are described in the advanced concepts of the protocol.

app/config/webauthn.yaml

webauthn:
    creation_profiles:
        acme:
            rp:
                name: 'ACME Webauthn Server'
            authenticator_selection_criteria:
                attachment_mode: !php/const Webauthn\AuthenticatorSelectionCriteria::AUTHENTICATOR_ATTACHMENT_PLATFORM
                require_resident_key: true
                user_verification: !php/const Webauthn\AuthenticatorSelectionCriteria::USER_VERIFICATION_REQUIREMENT_REQUIRED

Public Key Credential Parameters

This option indicates the algorithms allowed for your application. By default, a large list of algorithms is defined, but you can add custom algorithms or reduce the list.

The order is important. Preferred algorithms go first.

It is not recommended to change the default list unless you exactly know what you are doing.

app/config/webauthn.yaml

webauthn:
    creation_profiles:
        acme:
            rp:
                name: 'ACME Webauthn Server'
            public_key_credential_parameters:
                - !php/const Cose\Algorithms::COSE_ALGORITHM_ES256
                - !php/const Cose\Algorithms::COSE_ALGORITHM_RS256

Attestation Conveyance

If you need the attestation of the authenticator, you can specify the preference regarding attestation conveyance during credential generation.

Please note that the metadata service is mandatory to use this option.

The use of Attestation Statements is generally not recommended unless you REALLY need this information.

app/config/webauthn.yaml

webauthn:
    creation_profiles:
        acme:
            rp:
                name: 'ACME Webauthn Server'
            attestation_conveyance: !php/const Webauthn\PublicKeyCredentialCreationOptions::ATTESTATION_CONVEYANCE_PREFERENCE_DIRECT

Extensions

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.

The example below is tatolly fictive. Some extensions are defined in the specification but the supports depends on the authenticators and on the relying parties.

app/config/webauthn.yaml

webauthn:
    creation_profiles:
        acme:
            rp:
                name: 'ACME Webauthn Server'
            extensions:
                loc: true
                txAuthSimple: 'Please add your new authenticator'