/**
 * Utility class for sensitive data redaction in logs and API responses.
 *
 * Provides comprehensive data sanitization capabilities to prevent accidental
 * exposure of sensitive information. Supports recursive object traversal,
 * customizable sensitive field patterns, and specialized header redaction
 * for HTTP requests and responses.
 *
 * @class DataRedactor
 *
 * @example
 * ```typescript
 * // Basic data redaction
 * const userData = {
 *   name: 'John Doe',
 *   email: 'john@example.com',
 *   password: 'secret123',
 *   token: 'jwt-token-here',
 *   profile: {
 *     phone: '+1234567890',
 *     ssn: '123-45-6789'
 *   }
 * };
 *
 * const redacted = DataRedactor.redact(userData);
 * // Result:
 * // {
 * //   name: 'John Doe',
 * //   email: '[REDACTED]',
 * //   password: '[REDACTED]',
 * //   token: '[REDACTED]',
 * //   profile: {
 * //     phone: '[REDACTED]',
 * //     ssn: '[REDACTED]'
 * //   }
 * // }
 *
 * // Header redaction
 * const headers = {
 *   'authorization': 'Bearer jwt-token',
 *   'content-type': 'application/json',
 *   'cookie': 'session=abc123',
 *   'x-api-key': 'secret-key'
 * };
 *
 * const safeHeaders = DataRedactor.redactHeaders(headers);
 * // Result:
 * // {
 * //   'authorization': '[REDACTED]',
 * //   'content-type': 'application/json',
 * //   'cookie': '[REDACTED]',
 * //   'x-api-key': '[REDACTED]'
 * // }
 * ```
 */
export declare class DataRedactor {
    /**
     * Default sensitive field patterns that will be automatically redacted.
     * Includes common authentication, personal, and financial data fields.
     */
    private static defaultSensitiveFields;
    /**
     * Recursively redacts sensitive data from objects, arrays, and nested structures.
     *
     * Traverses through all levels of data structure and replaces values of sensitive
     * fields with '[REDACTED]'. Supports partial field name matching (case-insensitive)
     * and custom field patterns in addition to default sensitive fields.
     *
     * @param {any} data - The data to redact (object, array, or primitive)
     * @param {string[]} [sensitiveFields=[]] - Additional custom sensitive field patterns
     * @returns {any} Redacted data with sensitive values replaced
     *
     * @example
     * ```typescript
     * // Redact with custom fields
     * const customFields = ['internalId', 'employeeCode'];
     * const redacted = DataRedactor.redact(data, customFields);
     *
     * // Array handling
     * const users = [
     *   { name: 'John', password: '123', email: 'john@test.com' },
     *   { name: 'Jane', password: '456', email: 'jane@test.com' }
     * ];
     *
     * const safeUsers = DataRedactor.redact(users);
     * // Result: [
     * //   { name: 'John', password: '[REDACTED]', email: '[REDACTED]' },
     * //   { name: 'Jane', password: '[REDACTED]', email: '[REDACTED]' }
     * // ]
     *
     * // Nested object handling
     * const complexData = {
     *   user: {
     *     credentials: {
     *       username: 'john',
     *       password: 'secret',
     *       apiToken: 'token123'
     *     },
     *     contact: {
     *       phone: '1234567890',
     *       email: 'john@example.com'
     *     }
     *   }
     * };
     *
     * const safeComplexData = DataRedactor.redact(complexData);
     * // All sensitive fields at all nesting levels are redacted
     * ```
     */
    static redact(data: any, sensitiveFields?: string[]): any;
    /**
     * Redacts sensitive information from HTTP headers object.
     *
     * Specifically targets common authentication and session headers that may
     * contain tokens, API keys, or other sensitive authentication data.
     * Preserves non-sensitive headers while replacing sensitive ones with '[REDACTED]'.
     *
     * @param {Record<string, string | string[] | undefined>} headers - HTTP headers object
     * @returns {Record<string, string | string[]>} Headers with sensitive values redacted
     *
     * @example
     * ```typescript
     * // Express request header redaction for logging
     * app.use((req: Request, res: Response, next: NextFunction) => {
     *   const safeHeaders = DataRedactor.redactHeaders(req.headers);
     *   logger.info('Request received', { headers: safeHeaders });
     *   next();
     * });
     *
     * // Redacting fetch API headers
     * const response = await fetch(url, { headers });
     * const loggableHeaders = DataRedactor.redactHeaders(headers);
     * logger.debug('API request', { headers: loggableHeaders });
     *
     * // Header preservation example:
     * const headers = {
     *   'authorization': 'Bearer eyJhbGciOi...', // → '[REDACTED]'
     *   'content-type': 'application/json',      // → preserved
     *   'user-agent': 'Mozilla/5.0...',          // → preserved
     *   'x-api-key': 'sk_live_123456',           // → '[REDACTED]'
     *   'cookie': 'session=abc123'               // → '[REDACTED]'
     * };
     * ```
     */
    static redactHeaders(headers: Record<string, string | string[] | undefined>): Record<string, string | string[]>;
}