export declare function generateTwoFactorSecret(): string;
export declare function generateTwoFactorToken(secret: Secret): Promise<Token>;
export declare function verifyTwoFactorCode(token: Token, secret: Secret): Promise<boolean>;
/**
 * Generate an otpauth:// URI for two-factor authentication
 *
 * This URI can be used with any QR code library to generate a scannable
 * QR code for authenticator apps.
 *
 * @param user - User identifier (email or username)
 * @param service - Service name (e.g., 'StacksJS 2FA')
 * @param secret - Optional secret (will be generated if not provided)
 * @returns The otpauth:// URI string
 */
export declare function generateTwoFactorUri(user?: string, service?: string, secret?: Secret): string;
export type Token = string;
export type Secret = string;