IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING

Digital cryptography relies greatly on randomness in providing the security requirements imposed by various information systems. Just as different requirements call for specific cryptographic techniques, randomness takes upon a variety of roles in order to ensure the proper strength of these cryptographic primitives. This paper presents a 64-bit random number generator with a high generation speed and a good random sequences by employing the RC5 encryption algorithm round functions with some changes in the usage
of the key, where two keys have been used with an initial vector to start the sequence generator. This generator can be used as a keys generator for any security system or to generate an intermediate password for signing process, and it can be adapted in many other applications, such as random pattern generation, games, etc. Examining the sequences shows great results in terms of randomness and security by achieving a difference near 0.5, this value is the best result, and a high undependability on the previous generated sequences by also achieving a difference more than 0.5, frequency, serial and run test came out with a near optimality results.

Abstract – Encryption is mainly used to transmit the data over networks. There are so many techniques introduced which are used to protect the confidential image data from any unauthorized access. Multimedia data contains different types of data that includes text, audio, video, graphic, and images with the increasing use of multimedia data over internet; here comes a demand of secure multimedia data. Most of the encryption algorithm available is generally used for text data and not suitable for multimedia data. In this paper 256-bit RC5 in quadrate design has been proposed. It is a secret-key block cipher that uses good features of RC5 algorithm using another overall structure design. In RC5 quadrate design of F-functions will be used instead of rounds. To ensure improving the encryption performance; mainly for images characterized by reduced entropy, the implementation of both techniques has been realized for experimental purposes. Comparative study with traditional encryption algorithms shows the superiority of the modified algorithm.
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Keywords – Cryptography, Image Encryption, RC5, Quadrate Design,

Abstract: Network Security for data transmission is the most vital issue in modern communication systems. This paper discusses a new steganographic technique and the effectiveness of the proposed method is described through which the idea of enhanced security of data can be achieved. To hide data in a binary image, the proposed method focuses on the Least Significant Bit (LSB) technique in hiding messages in an image. The proposed method enhanced the LSB technique by randomly dispersing the bits of the message in the image and thus making it harder for unauthorized people to extract the original message easily.

Security and data confidentiality has become a critical issue for companies and
individuals. In a classical client-server network, the access control management is
performed on the server, relying on the assumption that the server is a trusted party. In
this paper, we focus on how to strengthen the data confidentiality in client-server
networks. We address the improving data confidentiality protocol by using symmetric
encryption based on different secret keys for each session derived from timestamp. This
key is generated in a local machine and without needing to exchange it between the client
and the server for encryption decryption process. We have to use symmetric encryption
without exchanging the secret key to ensure the security of information from attacks for
eavesdropping or modification.