Alexander G. Chefranov

Hill cipher modification based on eigenvalues HCM-EE

We propose and analyze a new modification of the Hill cipher, HCM-EE, generating dynamic encryption key matrix by exponentiation that is made efficiently with the help of eigenvalues. Security of HCM-EE is provided by the use of a large number of dynamic keys. Experimental results show that HCM-EE is from two to seven times more effective in the encryption quality of RGB bitmap images than Hill cipher and its known modifications in the case of images with large single colour areas, and slightly more effective otherwise. It is two times faster than HCM-H, having the best encryption quality among Hill cipher modifications compared versus HCM-EE.

Theory and Practice of Cryptography Solutions for Secure Information Systems

Information Systems (IS) are a nearly omnipresent aspect of the modern world, playing crucial roles in the fields of science and engineering, business and law, art and culture, politics and government, and many others. As such, identity theft and unauthorized access to these systems are serious concerns.Theory and Practice of Cryptography Solutions for Secure Information Systems explores current trends in IS security technologies, techniques, and concerns, primarily through the use of cryptographic tools to safeguard valuable information resources. This reference book serves the needs of professionals, academics, and students requiring dedicated information systems free from outside interference, as well as developers of secure IS applications. This book is part of the Advances in Information Security, Privacy, and Ethics series collection.

Elgamal public key cryptosystem and signature scheme in GU(m,p,n)

ElGamal public key cryptosystem and signature scheme is extended to the recently discovered group GU(m,p,n), of numbers co-prime to mpn and having analytical representation and known order. Elements of GU(m,p,n> with the maximal order are used as the base elements in the proposed extension instead of primitive roots used in the original scheme. Proposed scheme allows easy periodic change of the group and base elements to provide necessary security level without change of the prime number p contrary to the case of GF(p) used in the original ElGamal scheme. Computation of discrete logarithms in the proposed scheme is difficult for large p.

Secure Hill cipher modifications and key exchange protocol

The paper presents modifications of the Hill cipher generating dynamic encryption key matrix. The presented modifications provide better security and encryption quality than known ones. It also presents a protocol for secure key exchange similar to Diffie-Hellmans one, but using commutative matrices and matrix multiplication operations instead of time-consuming exponentiation.

One-Time Password Authentication with Infinite Hash Chains

One-time password scheme based on infinite forward stepping hash chains and not requiring re- initialization after a certain number of authentications is proposed. It resists known for such type schemes attacks, channel failures, and server side database compromise. p h p h h h n =

Secure true random number generator in WLAN/LAN

Wireless networks need more security in comparison to the other networks due to their intrinsic vulnerabilities to possible attacks. It is expected that by using a distributed method for true random number generators (TRNG) in wireless sensor networks (WSN) and wireless LAN (WLAN) randomness quality of generated numbers can be enhanced. We analyze a protocol for a distributed TRNG named ScatterLight (L. R. Giuseppe, M. Fabrizio and O. Marco, 2011) for a WSN. After making some changes on ScatterLight structure and physical data sources, the Enhanced ScatterLight protocol is introduced; it provides secure and high qualified true random numbers. Thus, the quality of randomness of obtained random numbers using National Institute of Standards and Technology tests is evaluated. Finally, by analyzing the results, it can be conducted that Enhanced ScatterLight protocol in comparisons with ScatterLight protocol in WLAN and LAN provides 60% and 53% better randomness quality respectively, while the performance is equal in both protocols.

Commutative Matrix-based Diffie-Hellman-Like Key-Exchange Protocol

A matrix-based Diffie-Hellman-like key exchange protocol and utilizing it secure key-exchange protocol similar to HMQV are proposed. The proposed key exchange protocol uses matrix multiplication operation only; it does not rely on the complexity of the discrete logarithm problem contrary to the prototype and its known variants. Two-way arrival at the common key, similar to that employed in the Diffie-Hellman protocol, is provided by specially constructed commutative matrices. The trap-door property ensuring the proposed protocol security is based on exploiting of a non-invertible public matrix in the key generating process.

Parameterized Improved Fast Encryption Algorithm for Multimedia PIFEA-M

Improved fast encryption algorithm for multimedia IFEA-M is modified to withstand recently discovered vulnerability to differential known plaintext-ciphertext attack. The proposed parameterized algorithm PIFEA-M has the same performance as FEA-M that is about 25% better than that of IFEA-M.

An effective hybrid swing-up and stabilization controller for the inverted pendulum-cart system

A new hybrid swing-up and stabilization controller (HSSC) for the inverted pendulum-cart system (IPCS) is proposed. The HSSC includes a fuzzy switching controller, a simple swing-up controller, and a fuzzy stabilization controller. The proposed HSSC can autonomously adapt its parameters according to the changes in the specification parameters of the IPCS without any need for an external adaptation mechanism. The comparison results illustrate the effectiveness of the proposed controller by improving the performance of the well-known SIRM FC [4] almost by 150%.

Pseudo-Random Number Generator RC4 Period Improvement

A new pseudo-random number generator algorithm RC4E, having period significantly greater than RC4 has, is proposed. It is an extension of RC4. It uses RC4 as a main engine and Heaps algorithm as a second engine, providing enumeration of all possible permutations. Second engine is invoked periodically and it resets the current state of the main engine. Experiments, conducted on the both algorithms, showed their good statistical properties and practically same performance