scholarly journals Enhancement of Non-Linear Generators to Calculate the Randomness Test for Frequency Property in the Stream Cipher Systems

Author(s):  
Ibrahim Abdul Rasool Hamoud
2019 ◽  
pp. 2229-2236
Author(s):  
Ahmed Amer Alsaadi ◽  
Ayad G. Naser Al-Shammari

In this paper, three main generators are discussed: Linear generator, Geffe generator and Bruer generator. The Geffe and Bruer generators are improved and then calculate the Autocorrelation postulate of randomness test for each generator and compare the obtained result. These properties can be measured deterministically and then compared to statistical expectations using a chi-square test.


2020 ◽  
Vol 10 (5) ◽  
pp. 6187-6190
Author(s):  
A. S. Alshammari

The keyspace of a cryptography system must be long enough in order to protect it from brute force attacks. The One-Time Pad (OTP) encryption is unconditionally secure because of its truly random keystream that is used only once. This paper proposes a new chaotic symmetric cryptosystem approach, comparable to OTP. The proposed system utilizes two Lorenz generators, a main and an auxiliary, where the aim of the second one is to make one of the main Lorenz generator’s parameters to vary continually with time in a chaotic manner. This technique was built on digitizing two Lorenz chaotic models to increase the security level. The scrambling scheme was developed and the Lorenz stream cipher binary stream successfully passed the NIST randomness test. The cryptosystem showed a high degree of security, as it had a keyspace of 2576, and it was compared with existing symmetric key cryptography systems, such as DES, 3DES, AES, Blowfish, and OTP.


Author(s):  
Dr .R. Siva Ram Prasad ◽  
G. Murali ◽  
S. Gopi Krishna

The main aim of this paper is to develop a new generation and innovative security software for applications. We proposed new stream cipher called NLFS. NLFS means Non-linear feedback stream cipher, which is a fast and secure stream cipher for egovernance applications. This stream cipher uses AES secure non-linear function and AES key generation. NLFS uses primitive polynomial generated S-boxes in byte substitution step. NLFS uses two similar AES round functions and these two proceed parallelly to produce key-stream. Non-linear *function of NLFS has AES nonlinear function steps (add-round key, byte substitution, mix column, shift rows) and it extra includes value-based rotation step. In value based rotation step it rotates each 8-bit word by its first 3-bit (decimal) value.NLFS have two modes basic mode that is synchronous mode and self synchronous mode. In synchronous mode key stream is independent of plain text and cipher text. In selfsynchronous mode key stream generation depending on cipher text. In self synchronous mode generated keystream update first 512-bit buffer and cipher text update the second buffer.


Living in this modern era – the epitome of communication GSM networks is one of the mainly used architectures. But GSM architecture has its own shortcomings; the GSM network is vulnerable to various security threats. For any network to provide security to the user, the algorithms should be planned and designed in such a way that it provides cellular secrecy, data and signaling confidentiality to the concerned user. Keeping in mind the above features, the A5/1 algorithm provides network security. Initially, the A5/1 algorithm dealt with a pre-defined secret key but they still possess the threat of being decrypted by cryptanalytic attacks. Although decrypting this algorithm is not easy and requires high computational power. Such attacks lead to the necessity to modify the A5/1 algorithm; in our paper, we have proposed a better method to enhance the already existing algorithm.


2014 ◽  
Vol 91 (12) ◽  
pp. 32-36
Author(s):  
K. Rajam ◽  
I. Raja Mohamed ◽  
K. J. Jegadish Kumar

2020 ◽  
Vol 23 (7) ◽  
pp. 1409-1419
Author(s):  
Hussain A. Younis ◽  
Israa M. Hayder ◽  
Israa Shakir Seger ◽  
Hameed Abdul-Kareem Younis

Author(s):  
Raja Muthalagu ◽  
Subeen Jain

ZUC is stream-cipher which generates 32-bit key-stream by using 128-bit initial key and 123-bit initial vector. It encrypts the plaintext data to produce cipher-text data. The 128-EEA3 encryption and 128-EIA3 authentication algorithms are based on ZUC which are specified for use in 3GPP cellular communications systems. The algorithm is divided in three stages: LFSR (Linear Feedback Shift Register), Bit Reorganization (BR) and, Non-Linear Function. In this paper, we are going to discuss about our modifications proposed for LFSR along with small change in operation of Non-linear Function which can reduce time for generating key-stream. Many attacks based on weakness of LFSR due to its linearity are proposed which in turn makes ZUC susceptible to various attacks based on LFSR. As we know in the structure of LFSR, non-linearity is provided in last block of LFSR by feedback operation while all other being clocked with previous value of LFSR, so we have introduced bit-shifting and circular shift operations on few blocks of LFSR output of which will be taken as input to other blocks of LFSR.  


1967 ◽  
Vol 28 ◽  
pp. 105-176
Author(s):  
Robert F. Christy

(Ed. note: The custom in these Symposia has been to have a summary-introductory presentation which lasts about 1 to 1.5 hours, during which discussion from the floor is minor and usually directed at technical clarification. The remainder of the session is then devoted to discussion of the whole subject, oriented around the summary-introduction. The preceding session, I-A, at Nice, followed this pattern. Christy suggested that we might experiment in his presentation with a much more informal approach, allowing considerable discussion of the points raised in the summary-introduction during its presentation, with perhaps the entire morning spent in this way, reserving the afternoon session for discussion only. At Varenna, in the Fourth Symposium, several of the summaryintroductory papers presented from the astronomical viewpoint had been so full of concepts unfamiliar to a number of the aerodynamicists-physicists present, that a major part of the following discussion session had been devoted to simply clarifying concepts and then repeating a considerable amount of what had been summarized. So, always looking for alternatives which help to increase the understanding between the different disciplines by introducing clarification of concept as expeditiously as possible, we tried Christy's suggestion. Thus you will find the pattern of the following different from that in session I-A. I am much indebted to Christy for extensive collaboration in editing the resulting combined presentation and discussion. As always, however, I have taken upon myself the responsibility for the final editing, and so all shortcomings are on my head.)


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