AuthenticatorResponse: clientDataJSON property
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 navigator.credentials.create()
or navigator.credentials.get()
. This property is only accessed on one of the child objects of AuthenticatorResponse
, specifically AuthenticatorAttestationResponse
or AuthenticatorAssertionResponse
.
Value
An ArrayBuffer
.
Instance properties
After the clientDataJSON
object is converted from an
ArrayBuffer
to a JavaScript object, it will have the following properties:
challenge
-
The base64url encoded version of the cryptographic challenge sent from the relying party's server. The original value are passed as the
challenge
option inCredentialsContainer.get()
orCredentialsContainer.create()
. crossOrigin
Optional-
A boolean. If set to
true
, it means that the calling context is an<iframe>
that is not same origin with its ancestor frames. origin
-
The fully qualified origin of the relying party 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.
tokenBinding
Optional Deprecated-
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
: A string 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.
Note:
tokenBinding
is deprecated as of Level 3 of the spec, but the field is reserved so that it won't be reused for a different purpose. -
topOrigin
Optional-
Contains the fully qualified top-level origin of the relying party. It is set only if it
crossOrigin
istrue
. type
-
A string which is either
"webauthn.get"
when an existing credential is retrieved or"webauthn.create"
when a new credential is created.
Examples
js
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
const clientDataStr = arrayBufferToStr(pk.clientDataJSON);
const 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