A Study of Reversible and Lossless Data Hiding Techniques in Encrypted

Abstract

Reversible data hiding a novel technique which is used to embed additional information in the encrypted images, applies in military and medical images, which can be recoverable with original media and the hided data without loss. The distribution of confidential data over the network requires more security. So, for improving security in data transmission, we can hide the data inside an encrypted image. Hence the confidentiality of the image and the data embedded in the image is maintained. The lossless scheme, the cipher text pixels are replaced with new values to embed the additional data into several LSB-planes of cipher text pixels by multi-layer wet paper coding. Then, the embedded data can be directly extracted from the encrypted domain, and the data embedding operation does not affect the decryption of original plaintext image. In the reversible scheme, a preprocessing is employed to shrink the image histogram before image encryption. The data embedded can be extracted without any error, and also the cover image can be restored with error free. This type of techniques is termed as Reversible Data Hiding. We are conducting a survey in this paper based on different Reversible data hiding techniques. In this technique the original image can be recovered losslessly. If we use a combined lossless and reversible data hiding techniques, one part of data can be extracted before image encryption and another confidential part can be extracted after encryption. The cipher text pixels are replaced with the additional data into new values to embed several cipher text pixels by wet paper coding at multiple layer. From original image the embedded data can be extracted and the original image can be recovered from the decrypted image directly. The embedded data can directly be extracted from the encrypted domain. The decryption of original plaintext image doesn’t affects data embedding operation. With the combined technique, before decryption a receiver may extract a part of embedded data, and recover the original plaintext image after decryption. A slight distortion is introduced due to the compatibility between the lossless and reversible schemes. The data embedding operations can be performed in the two manners simultaneously performed in an encrypted image and decrypted image.