EXOR Operator Research Articles

Design and analysis of ultralow-power all-optical EX-OR and OR logic operations with chiral Mach-Zehnder interferometer

Design and analysis of ultralow-power all-optical EX-OR and OR logic operations with chiral Mach-Zehnder interferometer

A lightweight group key management scheme with constant rekeying cost and public bulletin size

ABSTRACT Several group key management schemes have focused either on meeting security goals or efficiency. However, only a few works exist that address the issue of handling offline users. Trivially, existing schemes need to store all intermediate rekeying messages (for every join and leave operation) onto a public bulletin making them storage inefficient and key derivation costly. This article focuses on the challenges of making the group key management scheme lightweight and efficiently managing offline users. Toward this, we have proposed a group key management scheme based on binary key tree and ex-or operations. The proposed scheme, satisfying forward and backward secrecy requirements, has a constant rekeying cost, and users need to store only one secret key. The proposed scheme maintains the public bulletin board, which keeps rekeying information so that a user who went offline and missed rekeying operations gets the latest group key by using current rekeying messages. In the proposed scheme, the public bulletin is constant with the size of O ( n ) , independent of the number of rekeying operations. The proposed scheme is compared with the existing schemes and is found to be efficient and handles offline users more efficiently than other existing schemes.

Modified Symmetric Image Encryption Approach Based on Mixed Column and Substitution Box

Internet a network of interconnected systems which is used to transmit different kinds of sensitive data is made secure by encrypting this data during transmission and protecting it against any kind of violation. This paper presents a symmetric data encryption algorithm developed in Python to encrypt images, making the transmission secure. The major computations performed in the algorithm are Mix Columns, Key dependent ex-or operation with upper and lower triangular sections of the matrix, Shift Rows, and Customized Sub Bytes transformation which provides diffusion and confusion. Results of various analysis performed on the algorithm prove its authenticity, confidentiality, and integrity.

An electro-optic reconfigurable OR to Ex-OR gate based on microring resonator loaded on Mach–Zehnder interferometric structure

In this paper, we proposed a novel electro-optic reconfigurable OR to Ex-OR gate and vice-versa. The proposed design consists of two microring resonators (MRR), employed in parallel, in a Mach–Zehnder interferometric (MZI) structure’s upper and lower arms with a tunable phase shifter attached in its lower arm, and can be controlled externally. The design will work as an OR gate when the phase of the tunable phase shifter is 0, and it will work as an Ex-OR gate when the phase is ‘π’. The micro-ring resonator employs an electro-optic modulation technique based on carrier injection, with electrical voltage sets 2 V and -1.85 V respectively for logic 1 and logic 0. We have also studied the performance of the Ex-OR gate when the phase shift deviates from the ideal required value. The extinction ratio obtained for Ex-OR operation is 17 dB and for OR operation it is 7.58 dB respectively. To demonstrate the circuit’s working operation at a data rate of 10 Gbps, @1550 nm time domain simulations were carried out with two electrical information bit streams fed into it.

A secure image encryption scheme based on genetic mutation and MLNCML chaotic system

This paper presents a novel encryption scheme based on genetic operations and Mixed Linear-Nonlinear Coupled Logistic Map Lattice (MLNCML) spatiotemporal chaotic system. The initial values of the MLNCML system are related to the plain-image. Therefore, this scheme is sensitive to the plaintext and keys. For the simplicity and efficiency of the encryption process, expanded XOR (eXOR) operation and genetic operations are applied in the scheme. Spatiotemporal chaotic system can resist dynamical degradation and periodic phenomena, which offers good randomness for encryption. Moreover, the eXOR operation in this paper can effectively avoid the chosen-plaintext attack of traditional XOR operation. The DNA mutation and crossover operations are controlled by chaotic sequences, which overcome man-in-the-middle attack in the traditional DNA addition and subtraction operation. The experimental results indicate that the proposed scheme has good security to resist common attacks.

Enhancement of 3D-Playfair algorithm using dual key

Playfair cipher is the one of the well known polyalphabetic cipher. In this paper, we present a new approach for secure transmission of a message by a modified version of the Playfair cipher combining with the ex-or operation and dual key. To develop this whole technique we used the three functions. One is generated the matrix and another two is encryption and decryption technique. The proposed extended 3D-Playfair cipher is working with 256 (4 × 8 × 8) characters, it selected 52 alphabets (upper case and lower case), ten numerals and 194 most commonly used special characters of ASCII character set. We use the 3D version of the Playfair cipher but we use the digraph concept. The restrictions of existing 2D-Playfair ciphers and 3D-Playfair cipher using 4 × 4 × 4 matrices, 6 × 4 × 4 matrices are overcome in the proposed work. The proposed algorithm can accumulate more characters than the existing 3D-Playfair ciphers.

BHQRSM: Binary Hex Quadratic Residue Security Model to Enhance the Trust in MANETs

Mobile adhoc network (MANET) possesses various security challenges mainly due to its varying network topology. As central coordination is not possible in MANETs, sharing of keys between nodes is a difficult task. In this paper, we present a Binary Hex Quadratic Residue Security Model that does not require any kind of key distribution between the nodes in MANETs. We use a stream of equal weighted hex codes of decimal numbers and Ex-OR operations to generate a security vector which facilitates matching of code words and also determine the active and malicious nodes in the network. Our approach also saves energy as it requires less computational analysis when compared to existing approaches. We validate our approach through simulations results.

Security Analysis and Modification of Classical Encryption Scheme

Objectives: Computer security is all about the study of cyber attacks with a view to defend against them. Cryptography is considered to be a class of science by using the special art of transforming information in a protected way such that it can overcome the attacks. There is an immense requirement of strong cryptographic algorithms in order to withstand against the various attacks. Methods: The Kerchoff’’s Principle states that the encryption and decryption algorithms are always available to anyone. The security of the cipher against any sort of attack should be depends only on the secrecy of the key. There comes the play of cryptanalysis. It is art of breaking the keys by identifying the vulnerabilities existing in the systems. This paper deals with the classical encryption schemes and their cryptanalysis. The cryptanalysis for various encryption schemes differs a lot. Various cryptanalysis like statistical analysis, frequency analysis, trial and error (brute force) are carried out in this work. Findings: The classical encryption schemes such as caesar cipher, shift cipher, vigenere cipher, affine cipher and hill cipher are discussed in the paper. A detailed analysis about the security of the above mentioned ciphers are explored. Among the ciphers it is identified that if the key varies for each plaintext to be encrypted provides added security. But the worst is the management of the huge key space. A modified algorithm is proposed which can provide a better security using simple computations. In this approach lots of keys are used but generated from a single key by using simple shift and EXOR operation. In the main stream only one key need to be exchanged between the communication entities and for that exchange we can make use of the public key cryptosystem. Application: Cryptography is considered to be an ineluctable field in era of communication. Cryptographic algorithms acts as an underpinning for lots of applications such as Anonymous Remailers, Digital Signatures, Secured Money transactions etc.Keywords: Additive Cipher, Monoalphabetic Cipher, Multiplicative Cipher, Polyalphabetic Cipher

A Low Complexity Splitter Based Parallel Multiplier for DSP Applications

This paper proposes a splitter based parallel multiplier (SBPM) for both signed and unsigned numbers. The proposed SBPM reduces the number of partial products by a factor of two and demands lesser computational complexity compared to Booth multiplier. The synthesis report shows that SBPM is efficient when compared to Booth multiplier in terms of hardware requirements including number of multiplexers, Ex-OR operations, slices and 4 inputs look up table. Simulation result for 8 × 8 SBPM shows that the critical path delay is about 83.5 % of that of Booth multiplier for unsigned numbers and about 72.71 % for signed numbers.

Minimisation algorithm for three-level mixed AND-OR-EXOR∕AND-OR-EXNOR representation of Boolean functions

The AND-OR-EXOR form of a logic function comprises a pair of sum-of-products expressions (groups) connected by a single EXOR operator, such that the result realises the function. This paper presents several fast AND-OR-EXOR optimisation algorithms based on our previous technique for AND-OR-EXOR minimisation. It has been observed using benchmarks that this technique is able to produce results faster than our previous technique for most of the benchmarks without compromising the quality much. There are some functions which have a good AND-OR-EXOR representation, while there are others which have a good representation in the AND-OR-EXNOR or the mixed AND-OR-EXOR/AND-OR-EXNOR form. Keeping this in view a new heuristic minimisation algorithm for mixed AND-OR-EXOR/AND-OR-EXNOR forms is presented. A fast phase computation technique has been applied to several stages of the minimiser. The algorithm has been tested on many benchmarks and the results show that it is able to produce substantially better results for the majority of the benchmarks compared to any previously reported techniques. It has also been applied to adders and the results show that it is able to produce very good results for these.

A Wannier-Stark waveguide electroabsorption modulator as a low-power switch and its application as NAND, NOR or EXOR all-optical logic gates

A resistor-biased self-electro-optic-effect device in waveguide geometry has been realized with an electroabsorption modulator containing an InGaAs/InP superlattice as the waveguide core. Room-temperature all-optical switching has been experimentally observed over a wide wavelength range between 1.51 and 1.58 µm. Simulation of the device response to time-varying digital optical input signals shows that it is possible to obtain optical logic operation using these devices. Boolean functions such as NAND and NOR can be realized at 1.55 µm and EXOR operation at 1.51 µm at fairly low optical power levels. The functionality is however rather sensitive to optical bias power variations.

Heuristic AND-OR-EXOR three-level minimisation algorithm for multiple-output incompletely-specified Boolean functions

Given a logic function f, an AND-OR-EXOR representation of f comprises a pair of sum-of-products expressions connected by a single two-input EXOR operator such that the resulting expression realises f: The AND-OR-EXOR form of a logic function has been observed to have a more compact representation for functions like arithmetic, control, ALU circuits, etc. Compared to sum-of-products as well as EXOR-sum-of-products based representations. The problem of AND-OR-EXOR minimisation of logic functions is to find a suitable pair of sum-of-products expressions which will reduce the size of the representation and hence the resulting hardware. A new heuristic AND-OR-EXOR minimisation algorithm for multiple-output incompletely-specified logic functions has been developed. The algorithm is divided into two parts. The first part constitutes a new heuristic algorithm for decomposition of multiple-output incompletely specified logic functions for AND-OR-EXOR minimisation. The second part constitutes ANDOR-EXOR optimisation algorithms for multiple-output incompletely-specified logic functions. Using benchmark PLAs the authors show that their new AND-OR-EXOR minimisation algorithm is able to find better solutions than previous techniques.