Ahmed A. Abd El-Latif

A novel image encryption scheme based on substitution-permutation network and chaos

In this paper, a novel image encryption approach based on permutation-substitution (SP) network and chaotic systems is proposed. It consists of four cryptographic phases: diffusion, substitution, diffusion and permutation. Firstly, a diffusion phase is proposed based on new chaotic map. Then, a substitution phase based on strong S-boxes followed by a diffusion phase based on chaotic logistic map are presented which will, in turn, significantly increase the encryption performance. Finally, a block permutation phase is accomplished by a permutation function to enhance the statistical performance of the proposed encryption approach. Conducted experiments based on various types of differential and statistical analyses show that the proposed encryption approach has high security, sensitivity and speed compared to previous approaches A novel image encryption approach based on SP network and chaos is proposed.Qualitative and quantitative analysis verify the effectiveness of the proposed encryption scheme.The encryption scheme shows superior performance than previous schemes.

A new image encryption scheme based on cyclic elliptic curve and chaotic system

Recently, several cryptosystems based on chaos have been proposed. Nevertheless, most of them hinder the system performance, security, and suffer from the small key space problem. This paper introduces an efficient symmetric encryption scheme for secure digital images based on a cyclic elliptic curve and chaotic system that can overcome these disadvantages. The cipher encrypts 256-bit of plainimage to 256-bit of cipherimage within eight 32-bit registers. The scheme generates pseudorandom bit sequences for round keys based on a piecewise nonlinear chaotic map. Then, the generated sequences are mixed with the key sequences derived from the cyclic elliptic curve points. Results of statistical and differential analysis demonstrate that the proposed algorithm has adequate security for the confidentiality of digital images. Furthermore, it has key sensitivity together with a large key space and the encryption is fast compared to other competitive algorithms.

Breaking an image encryption scheme based on a spatiotemporal chaotic system

In this paper, we describe a cryptanalysis of image encryption scheme recently proposed by Chun-Yan Song, Yu-Long Qiao, and Xing-Zhou Zhang. The scheme is based on a spatiotemporal chaos with a dynamic keystream generator, and its security is claimed to rely in utilized the plainimage in the keystream generation process to obtain a different keystream for every plainimage/cipherimage pair. However, two flaws are investigated and prove that the security of the proposal against chosen plaintext attack is groundless. Simulations conducted demonstrate that the plainimage can be recovered under partial attack with an acceptable perceptual quality. Moreover, a total break is possible, but a large number of plain-image/cipher-image pairs is needed. HighlightsA cryptanalysis of an image encryption scheme based on spatiotemporal chaos is presented.We gave a complete and partial break of the cryptosystem under study.We prove that the studied cryptosystem is not sufficiently secure against chosen plaintext attack.Results suggest that a partial attach needs smaller number of plain/ciphered images with acceptable perceptual qualities.

Efficient modified RC5 based on chaos adapted to image encryption

RC5 is a well-known block cipher notable for its simplicity, speed, suitability for hardware and software implementation, and its low memory requirement. However, RC5 can be broken with various attacks, revealing weak security. This is mainly due to the poor diffusion operation that allows the cipher to be attacked with less complexity than that of the exhaustive search. In this work, we modify the RC5 to give high level security, and adopt it for image encryption by adjusting the structure of both the encryption routine and the key schedule. We generate round keys based on chaos. Then, we strengthen the diffusion operation by making heavy use of rotations. The security analysis of the modified cipher against several attacks is explored from a strict cryptographic viewpoint. Experimental results demonstrate that the modified RC5 provides an efficient and secure way for image encryption.

Chaotic watermark for blind forgery detection in images

In this paper, a new chaos based watermarking scheme for effective tamper detection in images is proposed. The proposed scheme is able to detect any possible forgery and spot the areas which have been tampered. To improve the efficiency of the proposed scheme, a binary watermark is constructed from the image itself, which makes the watermark unique for every image and guarantee the blindness in the detection process. To guarantee the security of the proposed scheme, chaotic maps are used to complicate the embedding and the detection process to reduce the vulnerability to different attacks. Experimental results and security analysis show that the proposed scheme achieves superior tamper detection under common attacks.

Linear discriminant multi-set canonical correlations analysis (LDMCCA): an efficient approach for feature fusion of finger biometrics

Feature fusion-based multimodal biometrics has become an increasing interest to many researchers in recent years, particularly for finger biometrics. There are, however, many challenges in fusing multiple feature sets, as the case with Canonical Correlation Analysis (CCA) and Multi-set Canonical Correlation Analysis (MCCA). How to extend them to fuse multiple feature sets is a significant problem in general. In this paper, we propose a novel multimodal finger biometric method, which provides feature fusion approach called linear discriminant multi-set canonical correlation analysis (LDMCCA). It combines finger vein, fingerprint, finger shape and finger knuckle print features of a single human finger. Compared with CCA and MCCA, LDMCCA contains the class information of the training samples and represents the fused features more efficiently and discriminatively in few dimensions. The experimental results on a merged multimodal finger biometric database show that LDMCCA is beneficial to fuse multiple features as well as achieves lower error rates than the existing approaches.

Selective image encryption scheme based on DWT, AES S-box and chaotic permutation

In this paper, a new selective encryption scheme based on DWT, AES S-box and chaotic permutation is proposed. The new scheme is composed of six steps: Image decomposition, Block permutation, DWT decomposition, substitution phase, chaotic permutation phase and reconstruction phase. Firstly, it generates four subbands, namely cAP, cVP, cHP and cDP, and encrypts only cAP subband, which contains the meaningful part of data. The proposed cryptosystem is evaluated using various security and statistical analysis. The performance tests show that the proposed scheme is secure against statistical and differential attacks.

Finger multibiometric cryptosystems: fusion strategy and template security

Abstract. We address two critical issues in the design of a finger multibiometric system, i.e., fusion strategy and template security. First, three fusion strategies (feature-level, score-level, and decision-level fusions) with the corresponding template protection technique are proposed as the finger multibiometric cryptosystems to protect multiple finger biometric templates of fingerprint, finger vein, finger knuckle print, and finger shape modalities. Second, we theoretically analyze different fusion strategies for finger multibiometric cryptosystems with respect to their impact on security and recognition accuracy. Finally, the performance of finger multibiometric cryptosystems at different fusion levels is investigated on a merged finger multimodal biometric database. The comparative results suggest that the proposed finger multibiometric cryptosystem at feature-level fusion outperforms other approaches in terms of verification performance and template security.

New Quantum Image Steganography Scheme with Hadamard Transformation

Based on Hadamard transformation and the novel enhanced quantum representation for quantum images (NEQR), a quantum image steganography scheme to embed a quantum text message into a quantum image is proposed. The extraction process can recover the text message with the stego image only. In the earlier works, there is no quantum image steganography algorithm to embed the quantum text message into a quantum image. The simulation results demonstrated that the proposed scheme has high-capacity, good invisibility, and high security.

Quantum Information Protocols for Cryptography

Quantum cryptography is a robust field of quantum computation and quantum information that focuses on protecting data secrecy by using properties of quantum-mechanical systems. Over the last few years, quantum cryptography has evolved into an emergent high-tech market with companies capable of delivering off-the-shelf products. This chapter introduces a succinct overview of some fundamental concepts of quantum computation, quantum information protocols and their use on the development of quantum cryptography protocols. Key concepts include quantum key distribution, quantum secret sharing, quantum secure direct communication, and deterministic secure quantum communication.