@simplewebauthn/server/esm/helpers/generateChallenge.js

SimpleWebAuthn for Servers

import { isoCrypto } from './iso/index.js';
/**
 * Generate a suitably random value to be used as an attestation or assertion challenge
 */
export async function generateChallenge() {
    /**
     * WebAuthn spec says that 16 bytes is a good minimum:
     *
     * "In order to prevent replay attacks, the challenges MUST contain enough entropy to make
     * guessing them infeasible. Challenges SHOULD therefore be at least 16 bytes long."
     *
     * Just in case, let's double it
     */
    const challenge = new Uint8Array(32);
    await isoCrypto.getRandomValues(challenge);
    return _generateChallengeInternals.stubThis(challenge);
}
/**
 * Make it possible to stub the return value during testing
 * @ignore Don't include this in docs output
 */
export const _generateChallengeInternals = {
    stubThis: (value) => value,
};