International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 5, May 2012)
Watermarking Approach towards Green Cryptography Neha Mehta1, Amit Joshi2 1
Department of Computer Science and Engineering, College of Technology and Engineering (CTAE), Maharana Pratap University of Agriculture and Technology (MPUAT), Udaipur, Rajasthan (India)
2
Department of Computer Science and Engineering, Pacific Academy of Higher Education and Research (PAHER) University, Udaipur, Rajasthan (India) 1
[email protected] 2
[email protected]
Abstract— Green Cryptography is a technique which enables a natural succession of cryptographic primitives. Cryptographic operations are made energy-efficient in a way that it promises the use of approaches of lightweight cryptography. These Lightweight cryptographic algorithms are certainly worn for the devices which use low or extremely low resources. In this paper we have proposed a watermarking scheme for digital images in order to ensure copyright protection and prevent malicious access. This technique will not only develop a secured system but at the same time they lay down very low resource requirements and, therefore, can be considered as trivial.
The goal of this work is to watermark the encrypted data without requiring the original signal. The algorithm take the advantage of multi resolution [9] feature of wavelet transform domain and non relevant features of cryptographic random signal .The interest is normally dictated by the need for better performance to satisfy a communication protocol or energy constraints. The question here lies as to why ECC? Because of its short key length and shortest processing time of 8-bit μC also it has short signatures which make it suitable for pervasive computing. Here, in ECC green cryptography we can sacrifice flexibility to save area by setting the design to fit a specific standardized binary-field curve that is quite reasonable for constrained devices. Standardized binary fields that provide short-term security (113 bits), as well as fields that are required for medium-term security applications Elliptic curve cryptosystem [1] is asymmetric and has shorter key lengths also easy for operation. An elliptic curve is defined by an equation is two variable, with coefficients. For the purpose of cryptography the variables and coefficients are limited to a special kind of set called a finite field. In elliptic curve cryptosystems, [10] the elliptic curve is used to define the members of the set over which the group is calculated i.e. an operation on any two elements of the set will give a result that is the member of the same set. The ability to take any two points on a specific curve, add them together, and get a third point on the same curve. The con-fusion in cryptography is that which two points were added together to obtain the third point.
Keywords: Watermarking, Elliptic Curve Cryptography, Discrete Cosine Transform.
I. INTRODUCTION Distinctive mechanisms considering the security aspects are watermarking and cryptography, respectively. The first one aims to insert a secret message, the watermark, into the to-be-protected data so that its existence is kept secret. To be effective, a watermark should not introduce perceivable object in the host data and it should be detectable also if unintentional or intentional modifications of the watermarked signal occurred. The State of the art is that watermarking methods embed the watermark bits into the most significant portions of the digital data, so that they cannot be removed without impairing the original content. In order to provide both levels of data protection, we propose a new commutative watermarking and encryption method for digital images. Our focus is to unite the robustness of a Discrete Cosine Transform watermarking method with the security provided by a suitable encryption algorithm. The proposed scheme is a simple algorithm with low computational complexity and consists of moderate image distortions. Therefore this scheme turns out to be a lightweight watermarking and it is suitable to be implemented in many applications. The goal of this work is to watermark the encrypted data without requiring the original signal.
II. RELATED WORK There is different categorization of digital watermark algorithms. First, watermark techniques can be divided into four groups according to the type of data to be watermarked [2]. Text watermarking 396
International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 5, May 2012) Image watermarking Video watermarking Audio watermarking Second, based on human perception, watermark algorithms are divided into two categories: Visible watermarking. Invisible watermarking. Visibility is associated with perception of the human eye so that if the watermark is embedded in the data in the way that can be seen without extraction, we call the watermark visible. Examples of visible watermarks are logos that are used in papers and video. On the other hand, an invisible watermarking cannot be seen by human eye. So it is embedded in the data without affecting the content and can be extracted by the owner or the person who has right for that. For example images distribute over the internet and watermarked invisible for copy protection. Finally, based on processing domain, watermark techniques can be divided into: Spatial domain: A watermark technique based on the spatial domain, spread watermark data to be embedded in the pixel value. These approaches use minor changes in the pixel value intensity. The simplest example of the former techniques is to embed the watermark in the least significant bits of image pixels (LSB). Transform domain: To have imperceptibility as well as robustness, adding of watermark is done in transform domain. In this method, transform coefficients are modified for embedding the watermark. Transform domain is also called frequency domain because values of frequency can be altered from their original. The most important techniques in transform domain are Discrete cosine transform (DCT) and Discrete Wavelet Transform (DWT). Yu and Chen proposed a blind watermarking scheme by using quantization and voting policies[3]. Wu and Hsieh used DCT zero tree to embed watermark [4]. Wang and Pearmain developed a blind watermarking technique by using relative modulation of the pixel value/DCT coefficient value[2]. Sun et al. proposed an algorithm based on General Gaussian Model [5]. Document [6] embedded the digital watermark in hadamard domain coefficients. However, the performances of blind watermarking algorithms are not good as non-blind ones [7].
III. PROPOSED METHEDOLOGY All paragraphs must be indented. Lightweight cryptographic algorithms like ECC have a short internal state, should have short processing time and lower communication cost. B’s Setup 1. Choose a medium prime number and an elliptic curve e. 2. Choose a point P on the curve e (i.e choose coefficients of elliptic curve equation y2=x3+a4x+a6) 3. choose a secret key, kB < e (no of points in e) 4. Compute point Q = [kb ]P 5. Send (P,Q,a4,p) to A 6. Keep secret kB A’s Setup 1. Obtain message, M, of size unit 8 values arranged in pairs . 2. Obtain watermark, W, of length binary bits,{1,1} 3. Select strength factor α 4. Select a secret key ka, such that 0
