Secure context
This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The attestationObject property of the AuthenticatorAttestationResponse interface returns an ArrayBuffer containing the new public key, as well as signature over the entire attestationObject with a private key that is stored in the authenticator when it is manufactured.

As part of the CredentialsContainer.create() call, an authenticator will create a new keypair as well as an attestationObject for that keypair. The public key that corresponds to the private key that has created the attestation signature is well known; however, there are various well known attestation public key chains for different ecosystems (for example, Android or TPM attestations).


attestObj = authenticatorAttestationResponse.attestationObject


After decoding the CBOR encoded ArrayBuffer, the resulting JavaScript object will contain the following properties:

The same as AuthenticatorAssertionResponse.authenticatorData. Note that in AuthenticatorAssertionResponse, the authenticatorData is exposed as a property in a JavaScript object while in AuthenticatorAttestationResponse, the authenticatorData is a property in a CBOR map.
The same AuthenticatorAssertionResponse.authenticatorData field is used by both AuthenticatorAttestationResponse and by AuthenticatorAssertionResponse. When used in attestation, it contains an optional field, attestedCredentialData. This field is not included when used in the AuthenticatorAssertionResponse. The attestedCredentialData field contains the credentialId and credentialPublicKey.
A text string that indicates the format of the attStmt. The WebAuthn specification defines a number of formats; however, formats may also be defined in other specifications and registered in an IANA registry. Formats defined by WebAuthn are:
  • "packed"
  • "tpm"
  • "android-key"
  • "android-safetynet"
  • "fido-u2f"
  • "none"
A an attestation statement that is of the format defined by "fmt". For now, see the WebAuthn specification for details on each format.


var publicKey = {
  challenge: /* from the server */,
  rp: {
    name: "Example CORP",
    id  : ""
  user: {
    id: new Uint8Array(16),
    name: "",
    displayName: "John Doe"
  pubKeyCredParams: [
      type: "public-key",
      alg: -7

navigator.credentials.create({ publicKey })
  .then(function (newCredentialInfo) {
    var attestationObj = newCredentialInfo.response.attestationObject;
    // This will be a CBOR encoded ArrayBuffer

    // Do something with the response
    // (sending it back to the relying party server maybe?)
  }).catch(function (err) {


Specification Status Comment
Web Authentication: An API for accessing Public Key Credentials Level 1
The definition of 'attestationObject' in that specification.
Recommendation Initial definition.

Browser compatibility

ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
attestationObjectChrome Full support 67
Full support 67
Full support 65
Notes Disabled
Notes Only supports USB U2F tokens.
Disabled From version 65: this feature is behind the Web Authentication API preference (needs to be set to Enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 18Firefox Full support 60
Full support 60
Notes Only supports USB U2F tokens.
IE No support NoOpera No support NoSafari Full support 13WebView Android Full support 70Chrome Android Full support 70Firefox Android Full support 60
Full support 60
Notes Only supports USB U2F tokens.
Opera Android No support NoSafari iOS Full support 13.3Samsung Internet Android Full support 10.0


Full support
Full support
No support
No support
See implementation notes.
See implementation notes.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also