Lossless data hiding for JPEG image with optimized Huffman table

Abstract

Lossless data hiding is a data hiding method that embeds secret data without distortion. In JPEG images, it generally refers to modifying the bitstream of the Huffman table and DCT coefficient, also known as the method of Huffman table modification. Currently, most JPEG lossless data hiding methods use coding redundancy in the default AC Huffman table. However, this preference is deficient in two ways. On the one hand, the Huffman tables of most JPEG images are optimized to save storage and increase transmission speed, causing the approach to be unavailable. In this paper, the embedding efficiency of each Run-Size (RS) has been analyzed, and an efficient mathematical model for the optimized Huffman table is established. On the other hand, current schemes tended to modify the AC Huffman table while ignoring the DC one. This is because the redundancy presented in the DC Huffman table is hard to exploit. In contrast, the modification on both optimized AC and DC Huffman tables (OAC, ODC) has been implemented in this paper. The experimental results show that the proposed scheme is superior in embedding capacity, file size preservation, and complexity without distortion compared to the state-of-the-art methods.