27-06-2012, 01:05 PM
Data Hiding in Encrypted Images
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INTRODUCTION
cryptography is the science of writing a secret code (or) the study of mathematical techniques related to aspects of information security such as confidentiality, data integrity, entity authentication and data origin authentication. The basic cryptographic schemes used are Symmetric (or) Secret key cryptography and Asymmetric (or) Public key cryptography. It employs complex computational algorithms for encryption and decryption. In order to reduce the complexity, Cryptography schemes can be used. The main need of cryptography is to hide the data with the secret key without knowing to the user.
Due to the fast progression of data exchange in electronic way, information security is becoming more important in data storage and transmission. Because of widely using images in industrial process, it is important to protect the confidential image data from unauthorized access. Security is an important issue in communication and storage of images, and encryption is one of the ways to ensure security.
ENCRYPTION SCHEME
Reversible Image Encryption and Data Hiding Method:
Several proposals have dealt with data hiding in image encryption implementations. The reversible data hiding scheme is used for encrypting the images. It is mainly used to embed additional message into some distortion, with a reversible manner so that the original content can be perfectly restored after extraction of the hidden messages. The proposed scheme is the content owner encrypts the original uncompressed image using an encryption key to produce an encrypted image. The data embedding algorithm hides data into the encrypted image using (least significant bit) LSB method with secret key.
CONCLUSION AND DISCUSSION
In this paper, we demonstrate that the image encryption algorithm is efficient and highly secure. All parts of the proposed encryption system were simulated using MATLAB. The scheme can resist most known attacks, such as statistical analysis and brute-force attacks. By comparing these entire algorithms the cat map transform gives the best image quality
and has high level of security with less computation. It is highly robust towards cryptanalysis.