LOSSLESS DATA HIDING BASED ON HOMOMORPHIC CRYPTOSYSTEM

Abstract : With the development of cloud server, reversible data hiding in encrypted domain has received widespread attention for management of encrypted media. Most of existing reversible data hiding methods are based on stream ciphers, which are mainly concerned with data storage security. While homomorphic ciphers focus on data processing security, which is popular in cloud and other third-party platforms. Reversible data hiding with homomorphic cryptography has been an active topic in the research filed. In this paper, we propose a new lossless data hiding method based on homomorphic cryptosystem. After a content owner generates encrypted media with homomorphic ciphers, a data hider embeds secret data by establishing a mapping between secret bits and losslessly modifying encrypted media. At the receiver side, the embedded data is extracted from encrypted domain with a little auxiliary message. And original media is recovered by directly decrypting marked encrypted media. During the embedding process, the modification of encrypted media does not change the corresponding original media owing to homomorphic and probabilistic properties. Thus, no distortion is introduced in the whole procedures of data embedding. And directly decrypted media containing embedded data is the same as the original media. Meanwhile, the proposed method achieves a high embedding rate through efficient mapping and skillful use of expanded pixel values. The experimental results show that compared with state-of-the-art methods, the proposed method has higher embedding rate without distortion.

 EXISTING SYSTEM :

 ? In the existing public key cryptosystem, the one with the highest encryption strength per bit is the difficulty of the ECC math problem, thus it is safe to encrypt images with EC-EG compared to using Paillier to encrypt images. ? When a new algorithm is produced or an existing algorithm is revised, intruders or hackers break the algorithm. ? The proposed scheme maintains (t, n) threshold of secret image sharing and obtains a better EC compared with the existing RDH-ED algorithms.

 DISADVANTAGE :

 ? The elliptic curve discrete logarithm problem is more difficult to deal with than the discrete logarithm problem on the finite field, and the security is also higher. ? This paper mainly uses polynomial interpolation technique to realize secret sharing and then solve the RDH problem for multiple receivers. ? In this paper, we address the issue concerning the separation of the roles of the data provider and the data processor, and both images and data are encrypted before transmission to the data processor.

 PROPOSED SYSTEM :

 • In this paper, a lossless data-hiding scheme for public-keyencrypted images is proposed. There are three parties in the scheme: an image provider, a data hider, and a receiver. • In our proposed scheme, after the space is reserved and encrypted, the MCC is constructed. The extra information is embedded into the bit plane of the corresponding plaintext by homomorphic addition. • The proposed scheme uses the homomorphic addition feature of EC-EG to protect the embedded extra information.

 ADVANTAGE :

 ? The image distortion is reduced, thus its performance is generally higher than the scheme in our paper. ? The distortion introduced by constructing MCGs is also getting larger and larger, which leads to faster performance degradation of the algorithm. ? The performance of our scheme is better than the one in when the embedded capacity is high. ? The method of statistical analysis can test the anti-attack performance of encryption algorithm in chaos and diffusion from different angles.