import type { TotpOptions } from './types/totp-options';
import type { VerifyOptions } from './types/verify-options';
/**
 * Time-based One-Time Password (TOTP) implementation per RFC 6238
 *
 * @param secret - Secret key as bytes (minimum 16 bytes)
 * @param opts - TOTP options including current time
 *
 * @returns Promise resolving to the TOTP code
 */
export declare const totp: (secret: Uint8Array, { algorithm, digits, period, now }?: TotpOptions & {
    now?: number;
}) => Promise<string>;
/**
 * Verify a TOTP code against a secret
 *
 * @remarks
 * Security: Uses constant-time comparison to prevent timing attacks (CWE-208).
 * Security: Always iterates through all windows to prevent leaking which time step matched.
 * Security: Validates window size to prevent DoS attacks (CWE-400).
 * Performance: Parallelizes code generation when window > 0.
 *
 * @param secret - Secret key as bytes (minimum 16 bytes)
 * @param code - Code to verify
 * @param opts - Verification options
 *
 * @throws ({@link InternalError}) - if window is invalid
 *
 * @returns Promise resolving to true if code is valid
 */
export declare const verifyTotp: (secret: Uint8Array, code: string, { algorithm, digits, period, window, now }?: VerifyOptions) => Promise<boolean>;