Web/API/AuthenticatorAttestationResponse/attestationObject

Secure contextThis 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).

Syntax

attestObj = authenticatorAttestationResponse.attestationObject

Properties

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

authData: 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.
fmt: 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"

attStmt: A an attestation statement that is of the format defined by "fmt". For now, see the WebAuthn specification for details on each format.

Examples

var publicKey = {
  challenge: /* from the server */,
  rp: {
    name: "Example CORP",
    id  : "login.example.com"
  },
  user: {
    id: new Uint8Array(16),
    name: "[email protected]",
    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) {
     console.error(err);
  });

Specifications

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

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`attestationObject`	Chrome 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 18	Firefox Full support 60 Notes' Full support 60 Notes' Notes' Only supports USB U2F tokens.	IE No support No	Opera No support No	Safari Full support 13	WebView Android Full support 70	Chrome Android Full support 70	Firefox Android Full support 60 Notes' Full support 60 Notes' Notes' Only supports USB U2F tokens.	Opera Android No support No	Safari iOS Full support 13.3	Samsung Internet Android Full support 10.0

Legend

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.