International Association
for Cryptologic Research

The historical domain of information hiding is alternatively used nowadays for communication security. Maybe the oldest and certainly one of the most studied field that falls in this category is steganography. Within the current paper, we focus on image steganography techniques in the case of the JPEG format. We propose a corrected and optimized version of the J3 stegosystem which, to the best of our knowledge and as shown throughout the paper, may be considered a very good choice in terms of security and efficiency as compared to current solutions. We reconstruct the entire J3 algorithm (pre-processing, message insertion and extraction) and detail all the modifications. We also present implementation optimizations and cover all practical cases while still using the maximum image insertion capacity.