PublicKeyCredentialCreationOptions.challenge

The challenge property of the PublicKeyCredentialCreationOptions dictionary is a BufferSource used as a cryptographic challenge. This is randomly generated then sent from the relying party's server. This value (among other client data) will be signed by the authenticator, using its private key, and must be sent back for verification to the server as part of AuthenticatorAttestationResponse.attestationObject.

Syntax

challenge = publicKeyCredentialCreationOptions.challenge

Value

A BufferSource which is at least 16 bytes long. Contains a cryptographic challenge emitted from the relying party's server which must be signed by the authenticator's private key and sent back (within the response) to the relying party's server for verification.

Examples

var publicKey = {
  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) {
    // 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

• AuthenticatorAttestationResponse.attestationObject which contains the signature of the challenge within its attStmt property.
• PublicKeyCredentialRequestOptions.challenge, the analogous option property used when fetching a credential.
• AuthenticatorAssertionResponse.signature which is produced using the challenge and the private key of the authenticator when fetching a credential.