/**
 * Password utility helpers for strength calculation and validation.
 *
 * Provides functions for password strength calculation, passphrase generation, and password validation.
 */
export declare const MEDIUM_SCORE_THRESHOLD = 0.5;
/**
 * Password strength levels.
 */
type PasswordStrengthLabel = 'Weak' | 'Medium' | 'Strong' | 'Very Strong';
/**
 * Converts a numeric password strength score to a human-readable label.
 *
 * @param score - The strength score (0-1).
 * @returns The corresponding strength label.
 *
 * @example
 * ```ts
 * const label = getPasswordStrengthLabel(0.8);
 * // label === 'Strong'
 * ```
 */
export declare function getPasswordStrengthLabel(score: number): PasswordStrengthLabel;
/**
 * Calculates the overall password strength combining diversity and entropy.
 *
 * @param password - The password to analyse.
 * @returns A strength score between 0 and 1.
 *
 * @example
 * ```ts
 * const strength = getPasswordStrength('Password123!');
 * ```
 */
export declare function getPasswordStrength(password?: string): number;
export {};