A Technique to Enrich the Secrecy Level of High Capacity Data Hiding Steganography Technique in JPEG Compressed Image

This paper proposes a technique that enriches the secrecy level of high capacity data hiding (HCDH) steganography technique. The main concept is to generate a Quantized DCT coefficient (QDCTC) of each 8x8 blocks of a cover image, to hide encrypted secret data inside those coefficients and finally to compress the image by entropy coding. Here, the QDCTC is generated using a Quantization table that can vary based on the quality factor. Now the secret data inside the QDCTC is embedded using data hiding capacity calculated by the capacity estimation equation. Then the secret data is encrypted by chaotic key sequence and embedded inside the cover image. At last, SHA-256 hash of secret data, r parameter of chaotic key sequence, capacity factor and uniformity factor are sent to the receiver after encrypting using RSA. However, the hiding technique of uniformity flag in HCDH technique is insecure. This security problem is resolved by combining Swap DCT technique. Thereby the proposed technique is suitable to hide any type of data inside JPEG compressed image. Finally, to evaluate the capacity and accuracy requirement, an experimental analysis is performed employing MSE, PSNR and capacity comparison between existing and proposed techniques.