Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 14 of 14
Full-Text Articles in Physical Sciences and Mathematics
Latin Squares: Critical Sets And Their Lower Bounds, Diane Donovan, Joan Cooper, D. J. Nott, Jennifer Seberry
Latin Squares: Critical Sets And Their Lower Bounds, Diane Donovan, Joan Cooper, D. J. Nott, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
In this paper we establish a number of new lower bounds on the size of a critical set in a latin square. In order to do this we first give two results which give critical sets for isotopic latin squares and conjugate latin squares. We then use these results to increase the known lower bound for specific classes of critical sets. Finally, we take a detailed look at a number of latin squares of small order. In some cases, we achieve an exact lower bound for the size of the minimal critical set.
Nonlinearity And Propagation Characteristics Of Balanced Boolean Functions, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Nonlinearity And Propagation Characteristics Of Balanced Boolean Functions, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Faculty of Informatics - Papers (Archive)
Three important criteria for cryptographically strong Boolean functions are balance, nonlinearity, and the propogation criterion. The main contributions of this paper are to reveal a number of interesting properties of balance and nonlinearity, and to study systematic methods for contructing Boolean functions that satisfy some or all of the three criteria. We show that concatenating, splitting, modifying, and multiplying (in the sense of Kronecker) sequences can yield balanced Boolean functions with a very high nonlinearity. In particular, we show that balanced Boolean functions obtained by modifying and multiplying sequences achieve a nonlinearity higher than that attainable by any previously known …
The Relationship Between Propagation Characteristic And Nonlinearity Of Cryptographic Functions, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
The Relationship Between Propagation Characteristic And Nonlinearity Of Cryptographic Functions, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Faculty of Informatics - Papers (Archive)
The connections among the various nonlinearity criteria is currently an important topic in the area of designing and analyzing cryptographic function. In this paper we show a quantitative relationship between propagation characteristics and nonlinearity, two critical indicators of the cryptographic strength of a Boolean function. We also present a tight lower bound on the nonlinearity of a cryptographic function that has propagation characteristics.
Applications Of Smartcards For Anonymous And Verifiable Databases, Thomas Hardjono, Jennifer Seberry
Applications Of Smartcards For Anonymous And Verifiable Databases, Thomas Hardjono, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
In this paper we describe a practical solution towards anonymous and verifiable databases based on the use of smartcards and the recent Improved Leighton-Micali protocol for the distribution of keys. The scheme is addressed particularly to public data held in separate government databases with the aim of preventing unauthorized government institutions from gathering and merging private data concerning individuals from these separate containers. The solution can be realized through the recent Clipper Chip and smartcard technology, and its security relies on the strength of these technologies. The scheme is also extendible to mobile computing environments.
The Weighing Matrices Of Order 4n And Weight 4n-2 And 2n-1, Marc Gysin, Jennifer Seberry
The Weighing Matrices Of Order 4n And Weight 4n-2 And 2n-1, Marc Gysin, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
We give algorithms and constructions for mathematical and computer searches which allow us to establish the existence of W(4n, 4n - 2) and W (4n, 2n - 1) for many orders 4n less than 4000. We compare these results with the orders for which W(4n, 4n) and W(4n, 2n) are known. We use new algorithms based on the theory of cyclotomy to obtain new T-matrices of order 43 and JM-matrices which yield W(4n, 4n - 2) for n = 5,7,9,11,13,17,19,25,31,37,41,43,61,71,73,157.
Structures Of Cryptographic Functions With Strong Avalanche Characteristics, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Structures Of Cryptographic Functions With Strong Avalanche Characteristics, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Faculty of Informatics - Papers (Archive)
This paper studies the properties and constructions of non linear functions, which are a core component of cryptographic primi- tives including data encryption algorithms and one-way hash function. A main contribution of this paper is to reveal the relationship between nonlinearity and propagation characteristic, two critical indicators of the cryptographic strength of a Boolean function. In particular, (we prove that (i) if f, a Boolean function on Vn, satisfies the propagation criterion with respect to all but a subset R of vectors in Vn, then the nonlinearity of f satisfies Nf ≥ 2 n-1 - …
Relating Nonlinearity To Propagation Characteristics, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Relating Nonlinearity To Propagation Characteristics, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Faculty of Informatics - Papers (Archive)
The connections among the various nonlinearity criteria is currently an important topic in the area of designing and analyzing cryptographic functions. In this paper we show a quantitative relationship between propagation characteristics and nonlinearity, two critical indicators of the cryptographic strength of a Boolean function. We also present a tight lower bound on the nonlinearity of a cryptographic function that has propagation characteristics.
Information Security In Mobile Databases, Thomas Hardjono, Jennifer Seberry
Information Security In Mobile Databases, Thomas Hardjono, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
During the last decade the decrease in the size of computing machinery, coupled with the increase in their computing power have lend to the development of the concept of mobile computing. Effects of this new vision can be seen currently in the flourishing numbers of mobile telephones and portable computing units. In the current work we investigate some issues concerning the security of databases and database systems in the mobile computing environment. We present a scheme for end-to-end secure data transfer between one mobile computing element to another based on a recent protocol for key distribution. Secure data transfer is …
Hybrid Predictive/Vq Lossless Image Coding, P O. Ogunbona, Jianli Wang, Golshah Naghdy
Hybrid Predictive/Vq Lossless Image Coding, P O. Ogunbona, Jianli Wang, Golshah Naghdy
Faculty of Informatics - Papers (Archive)
A multiplicative autoregressive model is used in a lossless predictive image coding scheme. The use of vector quantisation (VQ) for compression of the model coefficients leads to an improved compression ratio. Both image adaptive and universal codebooks are considered. A comparative analysis of the new coder is presented through simulation results.
Industrial Computer Vision Using Undefined Feature Extraction, Phil Evans, John A. Fulcher, Philip Ogunbona
Industrial Computer Vision Using Undefined Feature Extraction, Phil Evans, John A. Fulcher, Philip Ogunbona
Faculty of Informatics - Papers (Archive)
This paper presents an application of computer The implementation and operation of the system is vision in a real-world uncontrolled environment found at BHP Steel Port Kembla. The task is visual identification of torpedo ladles at a Blast Furnace wlahdilceh. is achieved by reading numbers attached to each 3. IMPLEMENTATION Number recognition is achieved through use of feature extraction using a Multi-Layer Perceptron (MLP) Artificial Neural Network (ANN). The novelty in the method used in this application is that the features the MLP is being trained to extract are undefined before the MLP is initialised. The results of the MLP …
New Feature-Based Image Adaptive Vector Quantisation Coder, Jamshid Shanbehzadeh, Philip O. Ogunbona
New Feature-Based Image Adaptive Vector Quantisation Coder, Jamshid Shanbehzadeh, Philip O. Ogunbona
Faculty of Informatics - Papers (Archive)
It is difficult to achieve a good low bit rate image compression performance with traditional block coding schemes such as transform coding and vector quantization, without regard for the human visual perception or signal dependency. These classical block coding schemes are based on minimizing the MSE at a certain rate. This procedure results in more bits being allocated to areas which may not be visually important and the resulting quantization noise manifests as a blocking artifact. Blocking artifacts are known to be psychologically more annoying than white noise when the human visual response is considered. While image adaptive vector quantization …
Information Security Issues In Mobile Computing, Thomas Hardjono, Jennifer Seberry
Information Security Issues In Mobile Computing, Thomas Hardjono, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
During the last decade the decrease in the size of computing machinery, coupled with the increase in their computing power has lend to the development of the concept of mobile computing. Effects of this new vision is currently evident in the flourishing numbers of mobile telephones and portable computing units. In this paper we investigate some issues concerning the security of mobile computing systems, within the framework of the categories of mobility, disconnection, data access modes and scale of operation (Imielinski & Badrinath, 1993). In contrast to previous works which concentrate on security in wireless communications, we focus on the …
Relationship Among Nonlinearity Criteria, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Relationship Among Nonlinearity Criteria, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng
Faculty of Informatics - Papers (Archive)
An important question in designing cryptographic functions including substitution boxes (S-boxes) is the relationships among the various nonlinearity criteria each of which indicates the strength or weakness of a cryptographic function against a particular type of cryptanalytic attack. In this paper we reveal, for the first time, interesting connections among the strict avalanche characteristics, differential characteristics, linear structures and nonlinearity of quadratic (S-boxes). In addition, we show that our proof techniques allow us to treat in a unified fashion all quadratic permutations (namely, quadratic (S-boxes that form permutations), regardless of the underlying construction methods. This greatly simplifies the proofs for …
New Normal Sequences Of Length 25, Marc Gysin, Jennifer Seberry
New Normal Sequences Of Length 25, Marc Gysin, Jennifer Seberry
Faculty of Informatics - Papers (Archive)
An introduction to binary sequences, combinatorial designs and how they are related to communication theory and computer security is given. An exhaustive search algorithm for normal sequences is presented. This is the first time that the lengths n = 24 and n = 25 have been searched through completely. No sequences of length 24 are found. It turns out that all the normal sequences of length 25 can be derived from Turyn sequences. This construction is subject to a new theorem that is given here.