Jsteg Algorithm Implementation for Information Hiding in JPEG Images

The Jsteg algorithm is a steganographic technique designed for embedding hidden information within JPEG images. It leverages the characteristics of JPEG compression by subtly modifying discrete cosine transform (DCT) coefficients to conceal data. The implementation involves analyzing quantized DCT coefficients from JPEG blocks and embedding secret bits by modifying the least significant bits (LSBs) of non-zero, non-one AC coefficients while preserving the statistical properties of the image. This approach enables information concealment with minimal visual impact, maintaining acceptable image quality for covert communication applications. The algorithm finds broad applications in digital watermarking, image encryption, and secure data transmission. Through Jsteg implementation, various types of information including text, images, and audio files can be embedded, supporting diverse steganographic requirements. Key implementation considerations include handling JPEG quantization tables, processing DCT coefficient arrays, and ensuring proper extraction algorithms that reverse the embedding process by reading LSB patterns from modified coefficients.