Deciphering a novel image cipher based on mixed transformed Logistic maps

Since John von Neumann suggested utilizing Logistic map as a random number generator in 1947, a great number of encryption schemes based on Logistic map and/or its variants have been proposed. This paper re-evaluates the security of an image cipher based on transformed logistic maps and proves that the image cipher can be deciphered efficiently under two different conditions: 1) two pairs of known plain-images and the corresponding cipher-images with computational complexity of $O(2^{18}+L)$; 2) two pairs of chosen plain-images and the corresponding cipher-images with computational complexity of $O(L)$, where $L$ is the number of pixels in the plain-image. In contrast, the required condition in the previous deciphering method is eighty-seven pairs of chosen plain-images and the corresponding cipher-images with computational complexity of $O(2^{7}+L)$. In addition, three other security flaws existing in most Logistic-map-based ciphers are also reported.Comment: 10 pages, 2 figure

Chosen-plaintext attack of an image encryption scheme based on modified permutation-diffusion structure

Since the first appearance in Fridrich's design, the usage of permutation-diffusion structure for designing digital image cryptosystem has been receiving increasing research attention in the field of chaos-based cryptography. Recently, a novel chaotic Image Cipher using one round Modified Permutation-Diffusion pattern (ICMPD) was proposed. Unlike traditional permutation-diffusion structure, the permutation is operated on bit level instead of pixel level and the diffusion is operated on masked pixels, which are obtained by carrying out the classical affine cipher, instead of plain pixels in ICMPD. Following a \textit{divide-and-conquer strategy}, this paper reports that ICMPD can be compromised by a chosen-plaintext attack efficiently and the involved data complexity is linear to the size of the plain-image. Moreover, the relationship between the cryptographic kernel at the diffusion stage of ICMPD and modulo addition then XORing is explored thoroughly

Agonistic behavior of captive saltwater crocodile, crocodylus porosus in Kota Tinggi, Johor

Agonistic behavior in Crocodylus porosus is well known in the wild, but the available data regarding this behavior among the captive individuals especially in a farm setting is rather limited. Studying the aggressive behavior of C. porosus in captivity is important because the data obtained may contribute for conservation and the safety for handlers and visitors. Thus, this study focuses on C. porosus in captivity to describe systematically the agonistic behaviour of C. porosus in relation to feeding time, daytime or night and density per pool. This study was carried out for 35 days in two different ponds. The data was analysed using Pearson’s chi-square analysis to see the relationship between categorical factors. The study shows that C. porosus was more aggressive during daylight, feeding time and non-feeding time in breeding enclosure (Pond C, stock density =0.0369 crocodiles/m2) as compared to non-breeding pond (Pond B, stock density =0.3317 crocodiles/m2) where it is only aggressive during the nighttime. Pond C shows the higher domination in the value of aggression in feeding and non-feeding time where it is related to its function as breeding ground. Chi-square analysis shows that there is no significant difference between ponds (p=0.47, χ2= 2.541, df= 3), thus, there is no relationship between categorical factors. The aggressive behaviour of C. porosus is important for the farm management to evaluate the risk in future for the translocation process and conservation of C. porosus generally

Implementation of a Symmetric Chaotic Encryption Scheme

Voice over Internet Protocol technology (VoIP) is progressing commendably, but packet loss, propagation delay, jitter, unreliable IP networks, and vulnerability to attacks by Internet hackers are among critical issues that have been identified. Voice privacy and security needs to focused upon and data encryption techniques are the answers in providing the security needed. However, traditional cryptosystems demand high computational complexity andhigh digital signal processors which in return increases the cost of implementation. There is parallel growth in cryptographic techniques which originated anintense research activity and the search for new directions in cryptography such as chaotic encryption. Due to its deterministic nature and its sensitivity to initial conditions, chaos has a certain potential in creating a newway of securing information to be transmitted or stored. There are two main objectives to this project. First is study the feasibility of the chaotic encryption scheme in providing a solution in to preserve data security while maintaining the voice quality for voice over Internet Protocol. Secondly, a new scheme based on a chaos system will be implemented for voice data. In order to achieve the second objective, a study had been carried out on other proposed schemes mainly the Hierarchical Data Security Protection (HDSP) for VoIP. This scheme performs two main operations which is the data-frame interleaving and intra-frame data encryption using bit swapping. Based onthe HDSP scheme, the author suggests a new scheme using two level encryption techniques, based on chaos. In this scheme, the author uses the bit swapping technique as the second encryption-decryption level and enhances it with a first level encryption-decryption scheme using the two's compliment overflow nonlinearity encoder-decoder pair. The implementation ofthis scheme is specified to do real time processing ofvoice data. It can also be used to read, encrypt and write a wave file. The entire system is implemented, tested and validated using MATLAB and Visual C++. Due to the promising prospect ofchaotic encryption in the field ofcryptography, and the lack ofimplementation ofthis new encryption-decryption algorithm, this project focuses on introducing a new symmetric encryption-decryption scheme based on a chaos system for VoIP

A chaotic image encryption scheme owning temp-value feedback

This paper presents a novel efficient chaotic image encryption scheme, in which the temp-value feedback mechanism is introduced to the permutation and diffusion procedures. Firstly, a simple trick is played to map the plain-image pixels to the initial condition of the Logistic map. Then, a pseudorandom number sequence (PRNS) is obtained from iterating the map. The permutation procedure is carried out by a permutation sequence which is generated by comparing the PRNS and its sorted version. The diffusion procedure is composed of two reversely executed rounds. During each round, the current plain-image pixel and the last cipher-image pixel are used to produce the current cipher-image pixel with the help of the Logistic map and a pseudorandom number generated by the Chen system. To enhance the efficiency, only expanded XOR operation and modulo 256 addition are employed during diffusion. Experimental results show that the new scheme owns a large key space and can resist the differential attack. It is also efficient.Comment: 10 pages, 4 figure

Recent Advancements on Symmetric Cryptography Techniques -A Comprehensive Case Study

Now a day2019;s Cryptography is one of the broad areas for researchers; because of the conventional block cipher has lost its potency due to the sophistication of modern systems that can break it by brute force. Due to its importance, several cryptography techniques and algorithms are adopted by many authors to secure the data, but still there is a scope to improve the previous approaches. For this necessity, we provide the comprehensive survey which will help the researchers to provide better techniques