08-02-2013, 04:43 PM
A New Algorithm for Image Encryption Based On n*n Block Displacement Followed By Symmetric Encryption
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Abstract:
The primary goal of this thesis is security management. This will provide authorization of users, and integrity, accuracy and safety of images which is traveling over internet. Moreover, an image-based data requires more effort during encryption and decryption. The Proposed Architecture for encryption and decryption of an image using suitable user-defined key is developed with the same objective. In this thesis, we introduce a new permutation technique based on the combination of pixel block interchanging and a new developed symmetric encryption algorithm called “A New Algorithm for Image Encryption Based On n*n Block Displacement Followed By Symmetric Encryption”. The selected image will divided into pixels blocks, which will be rearrange into a image using a interchanging process, and then the generated image will be encrypted using the Proposed symmetric encryption Algorithm.
Keyword: Encryption, Decryption, Security, Image, Cryptography, Algorithm
Introduction
An overview of Internet Security: Since the rise of the Internet one of the most important factors of information technology and communication has been the security of information. Everyday tons of data are transferred through the Internet through e-mail, file sharing sites, social networking sites etc to name a few. As the number of Internet users rises, the concept of Internet security has also gain importance. The fiercely competitive nature of the computer industry forces web services to the market at a breakneck pace, leaving little or no time for audit of system security, while the tight labour market causes Internet project development to be staffed with less experienced personnel, who may have no training in security. This combination of market pressure, low unemployment, and rapid growth creates an environment rich in machines to be exploited, and malicious users to exploit those machines.
In recent years, owing to frequent flow of digital images across the world over the transmission media, it has become essential to secure them from leakages. Many applications like military image databases, confidential video conferencing, medical imaging system, cable TV, online personal photograph album, etc. require reliable, fast and robust security system to store and transmit digital images. The requirements to fulfill the security needs of digital images have led to the development of good encryption techniques. During the last decade, numerous encryption algorithms have been proposed in the literature based on different principles. Among them, chaos based encryption techniques are considered good for practical use as these techniques provide a good combination of speed, high security, complexity, reasonable computational overheads and computational power etc. The digital images have certain characteristics such as: redundancy of data, strong correlation among adjacent pixels, being less sensitive as compared to the text data i.e. a tiny change in the attribute of any pixel of the image does not drastically degrade the quality of the image and bulk capacity of data etc Consequently, the traditional ciphers like IDEA, AES, DES, RSA etc. are not suitable for real time image encryption as these ciphers require a large computational time and high computing power. For real time image encryption only those ciphers are preferable which take lesser amount of time and at the same time without compromising security. An encryption scheme which runs very slowly, even may have higher degree of security features would be of little practical use for real time processes.
Information Security: In general, security denotes “the quality or state of being secure to be free from danger”. Security is classified into different layers depending on the type of content intended to be secured:
• Physical security: Defines the required issues that are needed to protect the physical data or objects from unauthorized intrusion.
• Personal security: It is defined as the security of the individuals who are officially authorized to access information about the company and its operations
• Operational security: It mainly relies on the protection of the information of a particular operation of the chain of activities.
• Communication’s security: The communication’s security encompasses the security issues regarding the organization’s communication media, technology and content.
• Network security: The network security is responsible for safeguarding the information regarding the networking components, connections and contents.
• Information security: Information security is the protection of information and the systems and hardware that use, store, and transmit that information. Information security can be defined as measures adopted to prevent the unauthorized use or modification of use of data or capabilities.
How Encryption Works
Cryptography technique is used Encryption and decryption word to implement its concept. Encryption mean systematic or step-by-step procedure called an algorithm to convert data or the plane text into unreadable form known as cipher text, its encrypted form. Decryption is also systematic or step-by-step procedure to convert cipher data or cipher text into original plane text. Encryption and Decryption normally require a string of characters called a key to encrypt or decrypt data respectively. Those who possess the key and the algorithm can encrypt the plaintext into cipher text and then decrypt the cipher text back into plaintext.
What is Cryptography?
We can characterize to Cryptographic systems into three ways:
The type o operations used for transformation plaintext to cipher text. All encryption algorithms are based on two general principles: substitution, in which each element in the plaintext is mapped into another element, and transposition, in which elements in the plaintext are rearranged. The fundamental requirement is that no information should be lost.
The number of key used. If both the sender and receiver are using the same key then it is refereed as symmetric, single-key, secret-key or conventional encryption. If sender and receiver each use a different key, the system is refereed as asymmetric, two-key or public-key encryption.
The way in which the plaintext is processed. A block cipher processes the input one block of elements at a time, producing an output block for each input block. A stream cipher processes the input elements continuously, producing output one element at a time.
Image Encryption:-
Nowadays, information security is becoming more important in data storage and transmission. Images are widely used in several processes. Therefore, the protection of image data from unauthorized access is important. Image encryption plays a significant role in the field of information hiding. Image hiding or encrypting methods and algorithms range from simple spatial domain methods to more complicated and reliable frequency domain ones. Most of the available encryption algorithms are mainly used for textual data and may not be suitable for multimedia data such as images.