import { SecureStorageConfig, SecureStorageInterface, SecureStorageResult, SecureStorageSetOptions, SecureStorageMetadata, StorageQuotaInfo, EncryptedData, EncryptionAlgorithm, EncryptedString } from './types';
/**
 * Secure Storage implementation with encryption
 *
 * Features:
 * - AES-GCM encryption with PBKDF2 key derivation
 * - Optional compression for large data
 * - Automatic expiration handling
 * - Storage quota monitoring
 * - IndexedDB fallback for large items
 *
 * @example
 * ```typescript
 * const storage = new SecureStorage('my-secret-key');
 *
 * // Store encrypted data
 * await storage.setItem('user-data', { name: 'John', email: 'john@example.com' });
 *
 * // Retrieve decrypted data
 * const result = await storage.getItem<{ name: string; email: string }>('user-data');
 * if (result.success) {
 *   console.log(result.data);
 * }
 *
 * // Check storage quota
 * const quota = await storage.getQuotaInfo();
 * console.log(`Using ${quota.usagePercent}% of storage`);
 * ```
 */
export declare class SecureStorage implements SecureStorageInterface {
    private readonly config;
    private readonly encryptionKey;
    private readonly storage;
    constructor(encryptionKey: string, options?: Partial<SecureStorageConfig>, useSessionStorage?: boolean);
    /**
     * Store an encrypted item
     */
    setItem<T>(key: string, value: T, options?: SecureStorageSetOptions): Promise<SecureStorageResult<void>>;
    /**
     * Retrieve and decrypt an item
     */
    getItem<T>(key: string): Promise<SecureStorageResult<T>>;
    /**
     * Remove an item
     */
    removeItem(key: string): Promise<SecureStorageResult<void>>;
    /**
     * Check if an item exists
     */
    hasItem(key: string): Promise<boolean>;
    /**
     * Get all keys
     */
    keys(): Promise<string[]>;
    /**
     * Get storage quota information
     */
    getQuotaInfo(): Promise<StorageQuotaInfo>;
    /**
     * Clear all secure storage items
     */
    clear(): Promise<SecureStorageResult<void>>;
    /**
     * Get item metadata
     */
    getMetadata(key: string): Promise<SecureStorageMetadata | null>;
    /**
     * Cleanup expired items
     */
    cleanup(): Promise<number>;
    /**
     * Get configuration
     */
    getConfig(): Readonly<SecureStorageConfig>;
    /**
     * Get the full storage key with prefix
     */
    private getStorageKey;
    /**
     * Estimate total storage size in bytes
     */
    private estimateStorageSize;
    /**
     * Create metadata for an item
     */
    private createMetadata;
    /**
     * Update last accessed time in metadata
     */
    private updateLastAccessed;
    /**
     * Get the type of value for metadata
     */
    private getValueType;
}
/**
 * Create a secure localStorage instance
 */
export declare function createSecureLocalStorage(encryptionKey: string, options?: Partial<SecureStorageConfig>): SecureStorage;
/**
 * Create a secure sessionStorage instance
 */
export declare function createSecureSessionStorage(encryptionKey: string, options?: Partial<SecureStorageConfig>): SecureStorage;
/**
 * Initialize the default secure storage instance
 * Call this once during app initialization
 */
export declare function initSecureStorage(encryptionKey: string): SecureStorage;
/**
 * Get the default secure storage instance
 * @throws Error if not initialized
 */
export declare function getSecureStorage(): SecureStorage;
/**
 * Check if secure storage is available
 */
export declare function isSecureStorageAvailable(): boolean;
/**
 * Securely wipe a string from memory
 * Note: This is best-effort in JavaScript due to string immutability
 */
export declare function secureWipe(value: string): void;
/**
 * Generate a secure encryption key
 * Returns a base64-encoded key suitable for SecureStorage
 */
export declare function generateEncryptionKey(length?: number): string;
/**
 * Hash sensitive data for storage keys
 * Use when the key itself should not reveal information
 */
export declare function hashForKey(data: string): Promise<string>;
export type { SecureStorageConfig, SecureStorageInterface, SecureStorageResult, SecureStorageSetOptions, SecureStorageMetadata, StorageQuotaInfo, EncryptedData, EncryptionAlgorithm, EncryptedString, };