/**
 * @param {object} params
 * @param {string | string[]} params.rpId
 * @param {string | Buffer} params.challengeSecret
 * @param {import('@exortek/challenge').IncrStore} params.challengeStore
 * @param {Array<{ id: string | Uint8Array, type?: string, transports?: string[] }>} [params.allowCredentials]
 * @param {'required' | 'preferred' | 'discouraged'} [params.userVerification]
 * @param {Array<'security-key' | 'client-device' | 'hybrid'>} [params.hints]
 * @param {number} [params.timeoutMs=60_000]
 * @param {object} [params.extensions]
 * @param {boolean} [params.conditional]
 * @param {string} [params.userId]
 * @param {string | number} [params.challengeExpiresIn='5m']
 * @param {string} [params.challengePrefix]
 * @returns {Promise<{
 *   options: Record<string, unknown>,
 *   challengeToken: string,
 * }>}
 */
export function begin(params: {
    rpId: string | string[];
    challengeSecret: string | Buffer;
    challengeStore: import("@exortek/challenge").IncrStore;
    allowCredentials?: {
        id: string | Uint8Array;
        type?: string;
        transports?: string[];
    }[] | undefined;
    userVerification?: "preferred" | "required" | "discouraged" | undefined;
    hints?: ("security-key" | "client-device" | "hybrid")[] | undefined;
    timeoutMs?: number | undefined;
    extensions?: object | undefined;
    conditional?: boolean | undefined;
    userId?: string | undefined;
    challengeExpiresIn?: string | number | undefined;
    challengePrefix?: string | undefined;
}): Promise<{
    options: Record<string, unknown>;
    challengeToken: string;
}>;