Fatih Özkaynak

Security problems for a pseudorandom sequence generator based on the Chen chaotic system

Abstract Recently, a novel pseudorandom number generator scheme based on the Chen chaotic system was proposed. In this study, we analyze the security weaknesses of the proposed generator. By applying a brute force attack on a reduced key space, we show that 66% of the generated pseudorandom number sequences can be revealed. Executable C# code is given for the proposed attack. The computational complexity of this attack is O(n) , where n is the sequence length. Both mathematical proofs and experimental results are presented to support the proposed attack.

Security analysis of an image encryption algorithm based on chaos and DNA encoding

Chaos and cryptography have some common features. Due to the close relationship, researchers try to combine the chaotic system with cryptosystem. Despite the many proposals that use various methods in the design of encryption algorithms, there is a definite need for a mathematically rigorous cryptanalysis of these designs. In this study, we analyze the security weaknesses of an image encryption algorithm based on DNA encoding and chaos. By applying chosen-plaintext attacks, we show that all the secret parameters can be revealed.

A new S-box construction method based on the fractional-order chaotic Chen system

Since substitution box (S-box) is the only nonlinear component related to confusion properties for many block encryption algorithms, it is a necessity for the strong block encryption algorithms. S-box is a vital component in cryptography due to having the effect on the security of entire system. Therefore, alternative S-box construction techniques have been proposed in many researches. In this study, a new S-box construction method based on fractional-order (FO) chaotic Chen system is presented. In order to achieve that goal, numerical results of the FO chaotic Chen system for

Analysis of chaotic methods for compression and encryption processes in data communication

a= 35, b=3, c=28

Role of NPCR and UACI tests in security problems of chaos based image encryption algorithms and possible solution proposals

a=35,b=3,c=28 and

Cryptographic random number generator for mobile devices

\alpha =0.9