/**
 * TOTP Authentication Provider
 *
 * Handles Time-based One-Time Password authentication.
 * Generates TOTP codes using HMAC-based algorithm.
 */
import { AuthProvider, AuthResult, TOTPAuthConfig } from './index.js';
export declare class TOTPProvider implements AuthProvider<TOTPAuthConfig> {
    readonly type: "totp";
    authenticate(config: TOTPAuthConfig): Promise<AuthResult>;
    clear(config: TOTPAuthConfig): Promise<void>;
    validate(config: TOTPAuthConfig): Promise<boolean>;
    private getCacheKey;
    /**
     * Generate TOTP code
     * Based on RFC 6238
     */
    private generateTOTP;
    /**
     * Convert counter to 8-byte array
     */
    private counterToBytes;
    /**
     * Decode Base32 string to Buffer
     */
    private base32Decode;
    /**
     * Get Node.js crypto module
     */
    private getCrypto;
}