Reversible Data Hiding using Visual Cryptography: A Review

ABSTRACT: Data security and data integrity are the two challenging areas for research. There are so many research is progressing on the field like internet security, steganography, cryptography. Data hiding are a group of techniques used to put a secure data in a host media with small deterioration in host and the means to extract the secure data afterwards. Reversible data hiding is a technique to embed additional message into some distortion-unacceptable cover media, such as military or medical images, with a reversible manner so that the original cover content can be perfectly restored after extraction of the hidden message. The reversibility means not only embedding data but also original image can be precisely recovered in the extracting stage. Most hiding techniques perform data embedding by altering the contents of a host media. These types of data hiding techniques are thus irreversible. However in a number of domains such as military, legal and medical imaging although some embedding distortion is admissible, permanent loss of signal fidelity is undesirable. This highlights the need for Reversible (Lossless) data embedding techniques. This paper gives a review on various reversible data hiding techniques and also proposes a novel approach for reversible data hiding using visual cryptography. This involves no use of keys thus keeping the computation cost for encryption/decryption low. This scheme applies a method of vacating the room for data prior to the image encryption used to hide the secret data. By reversing the order of encryption and data hiding we overcome the difficulty of finding the room for data from already encrypted image