/**
 * Validates the OTP template.
 * @param {string} template - Template to validate.
 * @returns {boolean} - True if the template is valid, false otherwise.
 */
export declare function validateTemplate(template: string): boolean;
/**
 * Generates an OTP based on a template.
 * @param {string} [template] - Template to generate OTP.
 * @returns {string} - Generated OTP.
 */
export declare function generateOtp(template: string): string;
/**
 * Generates a secure secret key with a random length.
 * @returns {string} - A hexadecimal string representation of the generated key.
 */
export declare function generateSecret(): string;