PNG Steganography from First Principles

This blog post explains PNG steganography using LSB encoding: it details PNG file structure (signature and chunks such as IHDR, IDAT, PLTE, IEND), scanline layout and filter types (None, Sub, Up, Average, Paeth), zlib/IDAT decompression, unfiltering algorithms, and provides C++ code for encoding and decoding payloads into PNG pixel data. The article demonstrates capacity calculations, discusses avoiding metadata-based approaches (like iTXt), shows how to safely reconstruct the PNG after embedding, and includes an extractor implementation to recover hidden data.