PublicKeyCredentialCreationOptions.extensions

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.

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.

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

Browser compatibility

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