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

The pubKeyCredParams property of the PublicKeyCredentialCreationOptions dictionary is an Array whose elements are objects describing the desired features of the credential to be created. These objects define the type of public-key and the algorithm used for cryptographic signature operations.

If this array contains multiple elements, they are sorted by descending order of preference.


pubKeyCredParams = publicKeyCredentialCreationOptions.pubKeyCredParams


An Array whose elements are objects with the following properties:


A string describing type of public-key credential to be created. As of this writing (March 2019), only "public-key" may be used.


A numeric identifier for the algorithm to be used to generate the key pair. The links between identifier and algorithms are defined in this IANA registry. Targeting ES256 (-7) and RS256 (-257) provides coverage for the vast majority of authenticators.

Though those elements are sorted by preference (the first element being the most preferred), it is up to the client to choose among those elements for building the credential.


var publicKey = {
  pubKeyCredParams: [
    // We would like an elliptic curve to be used if possible
      type: "public-key",
      alg: -7
    // If not, then we will fallback on an RSA algorithm
      type: "public-key",
      alg: -37
  challenge: new Uint8Array(26) /* this actually is given from the server */,
  rp: {
    name: "Example CORP",
    id  : ""
  user: {
    id: new Uint8Array(26), /* To be changed for each user */
    name: "",
    displayName: "John Doe",

navigator.credentials.create({ publicKey })
  .then(function (newCredentialInfo) {
    // send attestation response and client extensions
    // to the server to proceed with the registration
    // of the credential
  }).catch(function (err) {


Web Authentication: An API for accessing Public Key Credentials - Level 3 (Web Authentication)
# dom-publickeycredentialcreationoptions-pubkeycredparams

Browser compatibility

BCD tables only load in the browser

See also