Reversible Data Hiding with Hierarchical Embedding for Encrypted Images

Abstract : Reversible data hiding in encrypted images (RDHEI) is an effective technique of data security. Most state-of-theart RDHEI methods do not achieve desirable payload yet. To address this problem, we propose a new RDHEI method with hierarchical embedding. Our contributions are twofold. (1) A novel technique of hierarchical label map generation is proposed for the bit-planes of plaintext image. The hierarchical label map is calculated by using prediction technique, and it is compressed and embedded into the encrypted image. (2) Hierarchical embedding is designed to achieve a high embedding payload. This embedding technique hierarchically divides prediction errors into three kinds: small-magnitude, medium-magnitude, and largemagnitude, which are marked by different labels. Different from the conventional techniques, pixels with small-magnitude/largemagnitude prediction errors are both used to accommodate secret bits in the hierarchical embedding technique, and therefore contribute a high embedding payload. Experiments on two standard datasets are discussed to validate the proposed RDHEI method. The results demonstrate that the proposed RDHEI method outperforms some state-of-the-art RDHEI methods in payload. The average payloads of the proposed RDHEI method are 3.4568 bpp and 3.6823 bpp for BOWS-2 dataset and BOSSbase dataset, respectively.

 EXISTING SYSTEM :

  There are many novel reversible data hiding scheme for encrypted image available which are made up of image encryption, data embedding and dataextraction/image-recovery phases. In which the data of original cover are entirely encrypted and the additional message is embedded by modifying a part of encrypted data. At receiver side, with the aid of spatial correlation in natural image, the embedded data are successfully extracted while the original image is perfectly recovered. Some of the methods are discussed in next section. This paper is organized as follows in introduction Section general guidelines about cryptography and encryption. In Section 2 literature review on existing research paper.

 DISADVANTAGE :

 To address the above problems, we propose a new RDHEI method based on hierarchical embedding. The proposed RDHEI method is error-free and can reach a high payload. The main contributions of our work are summarized as follows. (1) A novel technique of hierarchical label map generation is proposed for the bit-planes of plaintext image. The hierarchical label map is calculated before image encryption by using prediction technique.During data embedding, it is firstly compressed and then embedded into the encrypted image. In addition, it is also used to assist exact data extraction and image recovery. (2) Hierarchical embedding is designed to achieve a high embedding payload meanwhile full reversibility is guaranteed.

 PROPOSED SYSTEM :

 • This work proposes a similar algorithm including the use of quantities of the random variable on the swarm of particles in order to estimate the next level. The main difference is their two stage procedure they first run the algorithm just to compute the levels and then they restart from the beginning with these proposed levels. Actually in this method it is shown that by computing the levels on the fly within the same run as the one to compute the rare event probability paid a small bias on the estimate. • Here they proposed a new way of analyzing the noise sensitivity of every pixel based on the local region image content such as texture, edge and luminance information and it can be done either embedded in the spatial domain or can beDCT coded to be embedded in the transform domain has a JPEG standard.

 ADVANTAGE :

 ? The RRBE-based methods can achieve good embedding performance, but they require extra pre-processing before image encryption, which increases computational cost for the content owner. ? To make high embedding capacity, some researchers are inclined to design specific encryption which can both provide confidentiality for original image and remain the redundancy within the encrypted image. ? Since spatial redundancy exists in the encrypted image, specific encryption based method can achieve better embedding performance than the stream cipher based VARE method. ? It can be seen that the ER results on the two databases also illustrate that the the ER of the proposed method reaches the best performance.