Optical image asymmetric cryptosystem using fingerprint based on iterative fraction Fourier transform

A novel asymmetric cryptosystem for optical image is proposed using fingerprint based on iterative fractional Fourier transform. To enhance the security, a hyperchaotic phase generated by a 4D Lorenz system is considered as the public key in the proposed encryption system, while the private key is emerged by the retrieved phase and fingerprint. In the encryption process, the secret information is hid into the hyperchaotic phase. Subsequently, the private key can be obtained by a reversible operation. To decrypt the original image, the ciphertext and private key are imported into the input plane of fractional Fourier system. This system is also applicable for information authentication because the fingerprint is used both in encryption and decryption approach. Some numerical simulations have been done to test the validity and capability of the encryption system.     

A new auto-switched chaotic system and its FPGA implementation

This paper presents a 3D chaotic system which is constructed by an auto-switched numerical resolution of multiple three dimensional continuous chaotic systems. The designed chaotic system provides complex chaotic attractors and can change its behaviors automatically via a chaotic switching-rule. Some complex dynamical behaviors are investigated and analyzed. The originality of the proposed architecture is that allows to solve the problem of the finite precision due to the digital implementation while provides a good trade-off between high security, performance and hardware resources (low power and cost). Hardware digital implementation and FPGA circuit experimental results demonstrate a promising technique can be applied in efficient embedded ciphering communication systems. Moreover, the proposed chaotic system should be very useful for the consideration of reducing negative influence of dynamical degradation in real-time embedded applications.     

Synchronized hybrid chaotic generators: Application to real-time wireless speech encryption

In this paper, a new stream key generator Hybrid Discrete Continuous Chaotic System (HDCCS) based on continuous and discrete chaotic systems is proposed. Our solution provides an easy and robust chaos synchronization while decrease the degradation due to finite precision during a digital implementation. Real-time application to wireless speech encryption effectively hides the original signal. Statistical security analysis for the proposed cryptosystem against cryptanalysis attacks, from a strict cryptographic viewpoint, are presented. These results verify and prove that the proposed speech cryptosystem is highly secure and has a very powerful diffusion and confusion mechanisms widely used in conventional cryptography.     

Determination of trihalomethanes in chlorinated sea water samples using a purge-and-trap system coupled to gas chromatography

In power stations, the cooling effluents are chlorinated to avoid excessive biofouling. Yet, this disinfecting treatment leads to the formation of halogenated by-products, mainly trihalomethanes. So, there is a need for precise and accurate methods that allow trace levels determination of these compounds. A system that combines purge-and-trap and gas chromatography (with an electron capture detector) was used in this study. After careful choice of the experimental conditions, the performance of the system were evaluated. Precise and accurate determinations were obtained, allowing the determination of trihalomethanes in sea water samples chlorinated on site in three French coastal power stations. Bromoform was the predominant component formed, while traces of dibromochloromethane, chloroform and bromodichloromethane were also detected.     

Robust hyperchaotic synchronization via analog transmission line

In this paper, a novel experimental chaotic synchronization technique via analog transmission is discussed. We demonstrate through Field-Programmable Gate Array (FPGA) implementation design the robust synchronization of two embedded hyperchaotic Lorenz generators interconnected with an analog transmission line. The basic idea of this work consists in combining a numerical generation of chaos and transmitting it with an analog signal. The numerical chaos allows to overcome the callback parameter mismatch problem and the analog transmission offers robust data security. As application, this technique can be applied to all families of chaotic systems including time-delayed chaotic systems.     

Determination of dihaloacetonitriles and halophenols in chlorinated sea water

The cooling effluents in power stations are chlorinated to avoid excessive biofouling. However, this disinfecting treatment leads to the formation of halogenated by-products, mainly trihalomethanes, haloacetonitriles and halophenols. There is therefore a need for precise and accurate methods that allow trace level determinations of these compounds. Experimental procedures combining liquid-liquid extraction and gas chromatography coupled to mass spectrometry were developed in this study to determine dihaloacetonitriles and halophenols. The extraction step was improved and the performance of both methods evaluated. Precise and accurate determinations were obtained, allowing the measurement of the investigated compounds in chlorinated sea water samples from three French nuclear power stations.     

Rapid determination of polycyclic aromatic hydrocarbons in sewage sludges using microwave-assisted solvent extraction. Comparison with other extraction methods

The presence of toxic organic micropollutants in municipal sewage sludges is a major problem on account of risks associated with the agricultural use of the sludges and therefore maximum tolerance limits are imposed. The aim of our study was to develop a reliable and fast analytical procedure for the determination of polycyclic aromatic hydrocarbons in sewage sludges, using focused microwave-assisted extraction. Optimization of the extraction conditions was performed on real matrices. The results of a 2(3) factorial design showed that extraction time was the only influential factor. The selected conditions (30 W, 10 min, 30 ml solvent) were used for real sludges and a certified marine sediment, leading to recoveries of between 56 and 75%. Results of an interlaboratory test confirmed these values. Finally, the technique was compared to traditional techniques (Soxhlet, sonication), and the more recent pressurized liquid extraction technique. Focused microwave-assisted extraction remains an attractive alternative technique due to its rapidity, the low solvent volume required and its moderate investment cost.