import { TOTPOptions, VerifyResult, QRCodeOptions } from './types';
/**
 * Generates a Time-Based One-Time Password (TOTP) according to RFC 623
 * @param secret The secret key as a string (Base32 encoded) or a Uint8Array
 * @param options Options for TOTP generation
 * @returns The generated TOTP code
 */
export declare function generateTOTP(secret: string | Uint8Array, options?: TOTPOptions): string;
/**
 * Verifies a Time-Based One-Time Password (TOTP) allowing for time skew
 * @param token The TOTP code to verify
 * @param secret The secret key as a string (Base32 encoded) or a Uint8Array
 * @param options Options for TOTP verification
 * @returns Result object with valid flag and time drift information
 */
export declare function verifyTOTP(token: string, secret: string | Uint8Array, options?: TOTPOptions): VerifyResult;
/**
 * Generates a QR code for easy TOTP setup with authenticator apps.
 * The QR code follows the 'otpauth://' URI format.
 * @param secret The secret key (Base32 encoded)
 * @param options Options for QR code generation
 * @returns Promise resolving to a data URL containing the QR code
 */
export declare function generateQRCode(secret: string, options?: QRCodeOptions): Promise<string>;
/**
 * Generates a random secret key in Base32 format for use with TOTP
 * @param length The length of the secret key in bytes (default: 20)
 * @returns Base32 encoded random secret
 */
export declare function generateRandomSecret(length?: number): string;