AuthenticatorResponse.clientDataJSON
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The clientDataJSON
property of the
AuthenticatorResponse
interface stores a JSON string in an
ArrayBuffer
, representing the client data that was passed to
CredentialsContainer.create()
or
CredentialsContainer.get()
. This property is only accessed on one of the
child objects of AuthenticatorResponse
, specifically
AuthenticatorAttestationResponse
or
AuthenticatorAssertionResponse
.
Value
An ArrayBuffer
.
Properties
After the clientDataJSON
object is converted from an
ArrayBuffer
to a JavaScript object, it will have the following properties:
type
-
A string which is either
"webauthn.get"
when an existing credential is retrieved or"webauthn.create"
when a new credential is created. challenge
-
The base64url encoded version of the cryptographic challenge sent from the relying party's server. The original value is passed via
PublicKeyCredentialRequestOptions.challenge
orPublicKeyCredentialCreationOptions.challenge
. origin
-
The fully qualified origin of the requester which has been given by the client/browser to the authenticator. We should expect the relying party's id to be a suffix of this value.
tokenBindingId
Optional-
An object describing the state of the token binding protocol for the communication with the relying party. It has two properties:
-
status
: A string which is either"supported"
which indicates the client support token binding but did not negotiate with the relying party or"present"
when token binding was used already -
id
: ADOMString
which is the base64url encoding of the token binding ID which was used for the communication.
Should this property be absent, it would indicate that the client does not support token binding.
-
Examples
function arrayBufferToStr(buf) {
return String.fromCharCode.apply(null, new Uint8Array(buf));
}
// pk is a PublicKeyCredential that is the result of a create() or get() Promise
var clientDataStr = arrayBufferToStr(pk.clientDataJSON);
var clientDataObj = JSON.parse(clientDataStr);
console.log(clientDataObj.type); // "webauthn.create" or "webauthn.get"
console.log(clientDataObj.challenge); // base64 encoded String containing the original challenge
console.log(clientDataObj.origin); // the window.origin
Specifications
Specification |
---|
Web Authentication: An API for accessing Public Key Credentials - Level 3 # dom-authenticatorresponse-clientdatajson |
Browser compatibility
BCD tables only load in the browser