/**
 * Stealth PNG decoder
 * Extracts metadata hidden in PNG alpha channel using LSB steganography
 * Based on the stealth_pngcomp format
 */
import { PNG } from 'pngjs';
import { SDMetadata } from './types';
/**
 * Extract Stealth PNG metadata from PNG object
 */
export declare function extractStealthPngMetadata(png: PNG): SDMetadata | null;
/**
 * Check if a PNG contains Stealth metadata
 */
export declare function hasStealthMetadata(png: PNG): boolean;
/**
 * Get Stealth metadata size (in bits)
 */
export declare function getStealthMetadataSize(png: PNG): number | null;
declare const _default: {
    extractStealthPngMetadata: typeof extractStealthPngMetadata;
    hasStealthMetadata: typeof hasStealthMetadata;
    getStealthMetadataSize: typeof getStealthMetadataSize;
};
export default _default;