IOSR Journal of Engineering (IOSRJEN) e-ISSN: 2250-3021, p-ISSN: 2278-8719 Vol. 3, Issue 10 (October. 2013), ||V1|| PP 16-27 www.iosrjen.org 16 | P a g e Design and implementation proposed system for encryption true images Asst. Prof. Dr.Baheja K.Shukur 1 , Ala aldeen abbas Abdulhassan 1, 2 Computer Technology /network department, Babylon University, Iraq Abstract: - Image encryption method prepared information unreadable. Therefore, no hacker or eavesdropper, including server administrators and others, have access to original message or any other type of transmitted information through public networks such as internet. This paper presented a secure encryption method for true image encryption, which gets the benefits of both methods (symmetric and asymmetric encryption methods); a hybrid technique is usually used. In this technique, asymmetric encryption (RSA) is used to encrypt the security message the resulting cipher text is converted to binary form then symmetric encryption designed to encrypt the resulted cipher bits by making XOR operation with it. The design of symmetric key provides good confusion and diffusion properties that ensures high security. The easiest way to do this is through the design of the strong threshold linear feedback shift register, where the R,G,B bytes is ciphered with a single distinct bit generated from making XOR operation between key generator and resulting binary cipher bits ,which made the ciphers are more complex, the key is said to be well designed and its size provides an upper bound of an algorithm’s cryptographic strength ,which consist of four shift registers the length them are 12,10,7,5 respectively, three of them are linear and the other are non- linear,also the design of the linear feedback function very strong ,which provided maximum length period. The opposite operation is performed to reconstructed the original image and the original secure message .in addition to that different measured have been used to explain the range of the difference between the regional and cipher images and to show the power of the encryption methods, such as histogram, Calibrated area, Mean, Standard deviation, Median, Calibrated center of mass , Calibrated perimeter, and Calibrated ferret diameter. Keyword: linear feedback shift register, RSA, symmetric cipher, asymmetric cipher. I. INTRODUCTION Information security is a description of each process that prevent unauthorized access or use of the data transmitted, that access or use may be takes the form of distortion, use, disclosure, modification, or disruption. The main use of cryptography is to provide the following criteria such as the confidentiality; integrity and availability of the information ignoring data form for protecting the interconnected and share the common services. Encryption changes the shape or location information so that does not allow unauthorized access or use of content. The strength of the encryption and decryption code system depends on the length and strength of the encryption key to prevent unauthorized person from access to the content of the text [1]. In the encryption and decryption process of a symmetric cipher both, must use the same key. Thus any messages can be decrypted the encryption key must be shared between the two persons. For this reason symmetric systems are known as shared secret systems or private key systems. Compared to asymmetric ciphers the Symmetric ciphers are significantly faster than asymmetric ciphers, but the requirements for key exchange make them difficult to use. In an asymmetric cipher, there are two kinds of functions and two different keys. As a result each person has two keys. One of them is, the public key, is shared publicly [2], while the other is the private key, should never be shared with anyone. The recipient's public key using to encrypt the message when you send a message using asymmetric cryptography. The recipient then decrypts the message using his private key. For this reason the system is called asymmetric. In this work the security massage for long length encrypted using RSA system, the resulted cipher text converted to the binary form then making XOR operation with the sequences bits resulted from threshold key generator for long 12,10,7,5 bits and strong feedback function. .Because the security of image data from unauthorized uses is important therefore; images are widely used in different-different processes. To protect confidential image data from unauthorized access so many image encryption techniques are available to be used [3]. For suitable access to and sharing a large number of digital images now transmitted over Internet and wireless networks through the developments of multimedia and networks technologies, [4], therefore the content of the Multimedia must be protected from an authorized by using method or a set of methods of security, which