The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

Organic–inorganic hybrid perovskite materials are attracting great interest for their applications in photovoltaics where they have demonstrated excellent efficiency. Here, Dou et al. demonstrate room temperature, solution-processed hybrid perovskite photodetectors with fast response and high detectivity.

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Solution-processed hybrid perovskite photodetectors with high detectivity

This review highlights the recent progress which has been made towards improved single-photon detector technologies and the impact these developments will have on quantum optics and quantum information science.

Single-photon detectors for optical quantum information applications

Chaos is good, if you are looking to send encrypted information across a broadband optical network. The idea that the transmission of light-based signals embedded in chaos can provide privacy in data transmission has been demonstrated over short distances in the laboratory. Now it has been shown to work for real, across a commercial fibre-optic channel in the metropolitan area network of Athens, Greece. The results show that the technology is robust to perturbations and channel disturbances unavoidable under real-world conditions. Chaotic signals have been proposed as broadband information carriers with the potential of providing a high level of robustness and privacy in data transmission1,2. Laboratory demonstrations of chaos-based optical communications have already shown the potential of this technology3,4,5, but a field experiment using commercial optical networks has not been undertaken so far. Here we demonstrate high-speed long-distance communication based on chaos synchronization over a commercial fibre-optic channel. An optical carrier wave generated by a chaotic laser is used to encode a message for transmission over 120 km of optical fibre in the metropolitan area network of Athens, Greece. The message is decoded using an appropriate second laser which, by synchronizing with the chaotic carrier, allows for the separation of the carrier and the message. Transmission rates in the gigabit per second range are achieved, with corresponding bit-error rates below 10-7. The system uses matched pairs of semiconductor lasers as chaotic emitters and receivers, and off-the-shelf fibre-optic telecommunication components. Our results show that information can be transmitted at high bit rates using deterministic chaos in a manner that is robust to perturbations and channel disturbances unavoidable under real-world conditions.

/pdf/chaos-based-communications-at-high-bit-rates-using-2z2lxtwks1.pdf

Chaos-based communications at high bit rates using commercial fibre-optic links

Squeezed states of the electromagnetic field have been generated by nondegenerate four-wave mixing due to Na atoms in an optical cavity. The optical noise in the cavity, comprised of primarily vacuum fluctuations and a small component of spontaneous emission from the pumped Na atoms, is amplified in one quadrature of the optical field and deamplified in the other quadrature. These quadrature components are measured with a balanced homodyne detector. The total noise level in the deamplified quadrature drops below the vacuum noise level.

Observation of squeezed states generated by four-wave mixing in an optical cavity

For the measurements of spectral attenuation of optical fibers in the range 800-1600 nm, an instrument based on a halogen-tungsten lamp pulsed at a few Hz has been designed and developed. This approach is shown to have substanstial advantages over the usual chopped-light technique. With a low-noise front-end photodiode preamplifier (-110 dBm sensitivity), the instrument offers a > 40 dB dynamic range of attenuation measurement in monomode fibers and can operate in analog as well as digital mode.

Spectral attenuation measurements of optical fibers: design of an instrument based on a pulsed-light source

Respiratory distress syndrome is a major cause of death of preterm newborns. This is due to the absence of lung surfactant. Non-invasive medical cares are in development, which need to know in real time the flow of surfactant instilled in the newborn. This work proposes the use of an optical flow sensor based on self-mixing interferometry. A dedicated prototype is realized for measuring surfactant flow rate in a small diameter duct, and its performances are evaluated.

Optical Flow Sensor for Lung Surfactant Delivery

Free propagation is a viable communication technique for short-distance and medium-bandwidth applications. Compared to a fiber-optics channel, it has the same high level of EMI ummunity, requires no installation work, is basically a mobile link, and can be implemented with very inexpensive components.

Design Charts for Optoelectronic Transmission via Free Propagation

Self-Mixing Technique for Sensing Application

The literature is relatively void on the macroscopic microbiological effects of laser radiation, particularly with respect to process applications. Excellent progress has occured in micro-chromosome  studies and  ultramacro skin/retina biomedical investigations. However, cellular microorganism studies have not been widely reported. The paper will recapitulate preliminary laboratory results conducted in the early '70s not previously presented at any conference (partly due to proprietary reasons) and summarize the results of recently completed studies. (Details which follow apply only to the recent investigation.) The laser used was a modified Synergetics Chromabeam 1070 dye laser with an energy output between 100 and 300 millijoules over a 400 nanosecond pulsewidth. Rhodamine 6G (orange) and 7-diethyiamino-4-methycoumarin (blue) were used as the lasing dyes. The microorganism used for the study was Escherichia coli maintained in cystine trypticase agar (CTA). Forty-eight hours before experimental irradiation,  the  microorganisms were transferred from CTA stock culture into tryptic agar slant. 3 x LO' cells were inoculated into 10 ml of plain nutrient broth solution, then incubated at 37\" C for 24 hours. The same procedure was used for 10 ml of photosensitizer-nutrient broth solution. The exogenous dyes used were acridine orange and new methylene blue, the former at a concentration of 1 x lo-' M/liter and the latter at 5 x lo-' Mjliter. A 1.0 microliter droplet of the microorganism suspension was deposited on a sterilized 24 x 30 mm microscope coverglass and placed in the irradiation chamber. (A control sample was kept under similar conditions, but away from the laser beam.) After irradiation to a predetermined energy level, the assembly was processed using standard asepticmicrobiological techniques and prepared for plate count. (Again, the control, save for irradiation, underwent a similar process.) After incubation for 24 hours at 37\" C, the plates (triplicates) were then counted under a stereoscopic microscope. The mean survival figure was then obtained by averaging the plate count of the irradiated samples and dividing by the average plate count of the control. A mean survival ratio (MSR): 1) greater than one, means catalysis or enhanced growth ; 2) one, means no apparent effect ; 3) less than one, means sterilization. The effect was minimal (MSR = 0.95) when no exogenous photosensitizer was used. The following MSR pattern resulted with photosensitizer. .. .. ~ . _______ -_-

Silvano Donati

Papers

Spectral attenuation measurements of optical fibers: design of an instrument based on a pulsed-light source

Optical Flow Sensor for Lung Surfactant Delivery

Design Charts for Optoelectronic Transmission via Free Propagation

Self-Mixing Technique for Sensing Application

Laser interferometer for sensing of respiratory sounds