Web/API/PublicKeyCredentialRequestOptions/challenge

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

The challenge property of the PublicKeyCredentialRequestOptions 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's private key and produce AuthenticatorAssertionResponse.signature which should be sent back to the server as part of the response.

Note: When the credential is created with a navigator.credentials.create() call, the signature of the challenge is contained within AuthenticatorAttestationResponse.attestationObject.

Note: A challenge will be at least 16 bytes long.

Syntax

challenge = publicKeyCredentialRequestOptions.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 options = {
  challenge: new Uint8Array([/* bytes sent from the server */])
};

navigator.credentials.get({ "publicKey": options })
    .then(function (credentialInfoAssertion) {
    // send assertion response back to the server
    // to proceed with the control of the credential
}).catch(function (err) {
     console.error(err);
});

Specifications

Specification	Status	Comment
Web Authentication: An API for accessing Public Key Credentials Level 1The definition of 'challenge' 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
`challenge` Experimental'	Chrome Full support 67	Edge Full support ≤79	Firefox Full support 60	IE No support No	Opera Full support 54	Safari Full support 13	WebView Android Full support 67	Chrome Android Full support 67	Firefox Android ?	Opera Android Full support 48	Safari iOS Full support 13.3	Samsung Internet Android No support No

Legend

Full support: Full support
No support: No support
Compatibility unknown: Compatibility unknown
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.