Secure context
This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
extensions
, an optional property of the PublicKeyCredentialCreationOptions
dictionary, is an object providing the client extensions and their input values.
Extensions are values requesting additional processing by the client and by the authenticator. For instance, extensions may be used for:
- backward compatibility with the legacy FIDO JS API,
- knowing the user verification process,
- etc.
Note: An analogous option exists for the fetching operation (navigators.credentials.get()
), see PublicKeyCredentialRequestOptions.extensions
.
Syntax
extensions = publicKeyCredentialCreationOptions.extensions
Value
An object with various keys and values.
Here is the current (as of March 2019) list of potential extensions which may be used during the registration operation.
Warning! As of June 2020, only appId
(used during creation with PublicKeyCredentialRequestOptions.extensions
) is supported by Chrome and Edge. Firefox does not seem to support any extension. Also Chrome doesn't plan to support any other extension in future
Extension identifier | Type | Description |
---|---|---|
authnSel |
Array of BufferSource |
Authenticator selection. Restricts the list of authenticator models which may be used. If no matching authenticator is available, the credential is still generated with another available authenticator. |
exts |
Boolean | Supported extensions. If true , the client outputs an array of strings containing the extensions which are supported by the authenticator. |
uvi |
Boolean | User verification index. If true , the client outputs an ArrayBuffer which contains a value uniquely identifying a user verification data record. In other words, this may be used server side to check if the current operation is based on the same biometric data that the previous authentication. |
loc |
Boolean | Location. If true , the client outputs a Coordinates object representing the geolocation of the authenticator. |
uvm |
Boolean | User verification method. If true , the client outputs an array of arrays with 3 values containing information about how the user was verified (e.g. fingerprint, pin, pattern), how the key is protected, how the matcher (tool used for the authentication operation) is protected. |
biometricPerfBounds |
Object with two numerical properties: FAR and FRR |
Biometric authenticator performance bounds. The client must not use any authenticator with false acceptance rate (FAR) and false rejection rate (FRR) below the inputs. The client outputs true if this was taken into account. |
Note: Extensions are optional and different browsers may recognize different extensions. All extensions are optional for the client to process them: if a browser does not know a given extension, that will not cause any failure, the extension simply will not be processed.
Examples
var publicKey = { extensions:{ uvi: true, loc: false, uvm: false, exts: true }, challenge: new Uint8Array(26) /* this actually is given from the server */, rp: { name: "Example CORP", id : "login.example.com" }, user: { id: new Uint8Array(26), /* To be changed for each user */ name: "jdoe@example.com", displayName: "John Doe", }, pubKeyCredParams: [ { type: "public-key", alg: -7 } ] }; navigator.credentials.create({ publicKey }) .then(function (newCredentialInfo) { // myBuffer will contain the result of any of the processing of the extensions var myBuffer = newCredentialInfo.getClientExtensionResults(); // send attestation response and client extensions // to the server to proceed with the registration // of the credential }).catch(function (err) { console.error(err); });
Specifications
Specification | Status | Comment |
---|---|---|
Web Authentication: An API for accessing Public Key Credentials Level 1 The definition of 'extensions' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
extensions | Chrome Full support 67 | Edge Full support ≤79 | Firefox Full support 60 | IE ? | Opera ? | Safari Full support 13 | WebView Android No support No | Chrome Android Full support 67 | Firefox Android ? | Opera Android ? | Safari iOS Full support 13.3 | Samsung Internet Android No support No |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- Experimental. Expect behavior to change in the future.
- Experimental. Expect behavior to change in the future.
See also
PublicKeyCredential.getClientExtensionResults()
- The list of all of the extensions defined in the specification
PublicKeyCredentialRequestOptions.extensions
, the analogous option property used when fetching a credential